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An introduction to electrical safety testing in accordance with IEC 62353 Innovating Together

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Page 1: An introduction to electrical safety testing in accordance with IEC … · 2016-07-19 · An introduction to electrical safety testing in accordance with IEC 62353 Innovating Together

An introduction to electricalsafety testing in accordancewith IEC 62353

Innovating Together

Page 2: An introduction to electrical safety testing in accordance with IEC … · 2016-07-19 · An introduction to electrical safety testing in accordance with IEC 62353 Innovating Together

1

Contents

Foreword 2

1 Introduction 3

1.1 Electrical Current 3

1.2 The Human Body 4

1.3 IEC 60601 Body Model 6

2 Medical Electronic Equipment 6

2.1 Commonly used terms and 7

definitions in IEC 62353

2.2 Symbols and Markings 8

2.3 Product Lifecycle 9

3 IEC 60601 10

3.1 In-Service Test Requirements 11

4 Introduction to IEC 62353:2014 12

4.1 How does IEC 62353 compare 13

with IEC 60601?

4.2 Technical Considerations 13

4.3 Test Frequency 14

4.4 Vital Preparation 14

5 Visual Inspection 14

6 Earth Bond Testing 15

6.1 Earth Bond Test Considerations 16

6.2 Precision vs Accuracy 17

7 Insulation Resistance Test 18

7.1 Insulation Resistance EUT to Earth 19

7.2 Insulation Resistance Applied Parts 20

7.3 Insulation Resistance Applied Parts 20

to Mains

7.4 Insulation Test Pass – Fail Limits 21

8 IEC 62353 Leakage Measurements 22

8.1 Method Characteristics 22

8.1.1 Direct Leakage 22

8.1.2 Differential Method 23

8.1.3 Alternative Method 24

8.2 Equipment Leakage 25

8.2.1 Equipment Leakage Direct Method 25

8.2.2 Equipment Leakage Differential Method 26

8.2.3 Equipment Leakage Alternative Method 27

8.3 Applied Part Leakage 28

8.3.1 Applied Part Leakage Direct Method 29

8.3.2 Applied Part Leakage 30

Alternative Method

8.4 Secondary Earth Problems 31

8.5 Live to Earth Voltage 33

9 Record Keeping 34

9.1 Comparing Data 34

10 Conclusion 35

10.1 Considerations and Recommendations 35

Appendix A 37

Pass / Fail Limits of IEC 62353

Appendix B 38

IEC 60601-1 Collateral Standards

Appendix C 39

IEC 60601-2 Particulars Standards

Appendix D 41

Patient Environment

Appendix E 42

Example Documentation Template

Innova t ing Togethe r

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Innovating Together

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Part of

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Foreword

This booklet is written as a guideline for peopleinvolved in testing medical electrical equipment(ME equipment).

The aim of this booklet is to help the reader to:

n Appreciate the basics of electrical safety.n Understand the reasons behind and the

purpose of the IEC 62353 publication.n Provide an understanding of the benefits of

using the different tests available, in order tohelp them prepare the adoption of the IEC62353 standard.

This booklet cannot be considered as areplacement for the IEC 62353 publication,which can be purchased through the official IECwebsite, www.webstore.iec.ch.

All reasonable care has been taken to ensure theaccuracy of the information, reference figuresand data has been taken from the latest versions

of various standards, guidance notes andrecognised ‘best practices’ to establish therecommended testing requirements. However,Rigel Medical, their agents and distributors,accept no responsibility for any error oromissions within this booklet, or for any misinter-pretations by the user.

For clarification on any part of this booklet,please contact Rigel Medical before operatingany test instrument, under relevant legislation.

No part of this publication shall be deemed toform, or be part of, any contract for training orequipment unless specifically referred to as aninclusion within such contract.

Rigel Medical assumes that the readers of thisbooklet are electronically technically competentand therefore, does not accept any liability arisingfrom accidents or fatalities resulting directly orindirectly from the tests described in this booklet.

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1 Introduction

This guide covers a basic introduction toelectrical safety, definitions of a medicalelectronic device, the IEC 60601 standard and an in-depth overview of the IEC 62353publication.

The structure and topics discussed in this guideare written in a way such that the widest possibleaudience can benefit.

1.1 Electrical CurrentElectrical current is a secondary energy formconsisting of the flow of charge (in coulomb)through a circuit over a certain time period, andis depicted in ampere.

1 = Q/t or 1 Ampere = 1 Coulomb/1 second

When electrical current passes through aconductor or electrical circuit, it generates anelectrical potential (depicted in volt), see figure 1.

Figure 1: Ohm's Law

There is a directly proportional relationshipbetween the electrical current (ampere) throughand the electrical potential (volt) across theconductor (ohm). This is commonly known asOhm’s law.

V (a – b) = I * R

The force required to deliver the electrical currentacross a potential difference is known as power,which is represented in Watt’s. Power is aproduct of voltage (volt) and current (ampere):

Another factor of electricity is electrical energy(joules), a product of electrical power (watts orjoules/second) and time (seconds). Therelationship is provided below:

The relationship between current, voltage andresistance can be equally applied to waterrunning through a pipe. In both cases, electriccurrent and water prefer the path of leastresistance. The larger the cross section of thepipe or conductor, the easier water or currentcan flow at a certain water pressure or voltage.See figure 2.

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Rigel Medical Company Profile

The healthcare market is technology driven and with a global demand for increased patient safety,there has never been a more prudent time to demand more from your test equipment.

International standards for the development and manufacturing of medical devices put greateremphasis on risk assessment and analyses of data. So, there is an increased need for test equipmentthat allows the user to automate data capture and ensure validity of test results for better managementof risk.

Our range of dedicated biomedical test equipment is vital in verifying the safety, accuracy andperformance of medical devices, and has become intrinsic to the endeavour to raise the standard ofpatient safety across the globe.

Rigel Medical products are sold worldwide through an international network of agents and distributors.

Rigel Medical is part of the Seaward Group of companies.

Conductor resistance (R)

Electrical current (I)

Electrical potential (Va-Vb)

Ohm’s Law

V(a-b) = I x R

A B

Power in WattsP = V x I

Power in WattsP = I² x R

Power in WattsP = V² / R

Energy in JsE = P x t

Energy in JsE = (V² x t) / R

Energy in JsE = I² x R x t

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Figure 2: Example showing water followingpath of least resistance

n The thinner or longer the water pipe, the morewater pressure is required to deliver the samelitres per minute (flow or current).

n The thinner or longer the conductor (assuminga particular specific resistance of material), themore voltage is required to deliver the samecurrent.

1.2 The Human BodyA significant part of the human body is made upof water along with dissolved ions and minerals,which are capable of conducting electricalcurrents. Broadly speaking, the hazard of suchelectrical currents would depend on:

n Strength of the currentn Path of the currentn Total impedance for the current pathn Frequency of the currentn Duration of the current being applied

Electrical currents can be extremely dangerousto the human body. The energy (power and timefactor) released by electrical current passingthrough human tissue can generate burns and

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excite or stimulate muscles of the respiratorysystem (intercostals).

The most critical muscles are those in the humanheart, which are driven (excited) by very tinyamounts of electrical currents. When the heart isexposed to external electrical currents (electricalshock), the heart can lose its normal sinusrhythm, required to sustain a healthy bloodcirculation, and move into ventricular fibrillation.This stops the circulation of oxyhaemoglobin(oxygenated blood cells) to the brain and organsand when left untreated, will result in death within15 minutes.

Ironically, the most common treatment ofventricular fibrillation is the use of a defibrillatorwhich delivers a very high current pulse, up to100A across the heart. The energy in that highcurrent pulse is sufficient to temporarily clampthe heart muscles (ie stop the heart completely)before releasing it again and allowing the heart toresume in its normal sinus rhythm.

Consider the following examples of a macroshock showing the effect of a 50 / 60 Hz currenton the human body when applied to the skin for1 – 3 seconds (non-invasive):

0.5 -1.1 mA Current just noticeable whenapplied to the finger tip

6 – 16 mA Painful shock, unable to let go,cannot be tolerated over 15 minutes

75-400 mA Ventricular fibrillation, respiratoryarrest, leading to death

<1 A Serious burns and muscular contractionof such a degree that the thoracicmuscles constrict the heart

(Data adapted from published research byProfessor C.F. Dalziel)

The graph below (figure 3) highlights the differenteffects of electrical current on the human body asunderstood by Dr. Howard M. Hochbergi.

Figure 3: Impact of current on the humanbody, adapted from research by Howard M.Hochberg, 1971

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Heart defibrillation

Severe burnsHeart clamps - no fibrillation

Severe risk of macroshockVentricular fibrillationBreathing problemsMuscular paralysisLet go threshold

Perception of shockSevere risk of microshockVentricular fibrillation

Increased risk of microshockSafe

6A

1A

200 mA

100 mA

10 mA

1 mA

100 uA

10 uA 0 uA

Water Electricity

Current or flow Litre / second Current Ampere (coulomb / second)

Pressure e.g. BAR or PSI Voltage Volt

Resistance Effected by pipe cross section andlength

ResistanceIn ohm (Ω). Effected by conductorcross section, length and material

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1.3 IEC 60601 Body ModelTo ensure a standardised method of simulatingthe impedance of the human body,measurement circuits have been designed tosimulate the average, typical electricalcharacteristics of the human body. Thesemeasurement circuits are referred to as a BodyModel or Measuring Device (MD in IEC 60601-1).

The main impedance is formed by a 1kΩ resistor,shown in figure 4.

Figure 4: Example of a measuring deviceMD to IEC 60601

2 Medical Electronic Equipment

Heath facilities including hospitals, surgeries, GPpractises, veterinarian clinics, dentists etc. use avariety of electrical equipment. The equipmentranges from specialist medical, laboratory and ITequipment to ordinary domestic appliances.

Any electrical equipment for the purpose oftreating, monitoring or diagnosing a patient’scondition is classed as a medical electronicdevice according to IEC 60601, the globalharmonised standard governing the design andapproval of medical devices (see 3).

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The official definition of medical electricalequipment according to IEC 60601 is:

“Electrical equipment, designed fortreatment, monitoring or diagnoses ofpatients, powered from not more than oneconnection to mains supply and which arenecessarily in physical or electrical contactwith the patient or transfers energy to orfrom the patient or detects such energytransfer to or from the patient.”

Medical and non-medical electronic equipmentcan also be combined into a medical electronicsystem. To ensure safety of patient and operator,this system must meet the design requirementsof IEC 60601.

The definition of a medical electronic system is;

“Combination of equipment of which atleast one is classed as medical electricalequipment and as such specified by themanufacturer to be connected by functionalconnection or use of a multiple portablesocket-outlet.”

2.1 Commonly used terms and definitions in IEC 62353 / 60601

Equipment under testThe equipment (EUT) which is the subject oftesting.

Device under testThe device (DUT) which is the subject of testing.

Applied partPart of the medical equipment, which is designedto come into physical contact with the patient, orparts that are likely to be brought into contactwith the patient.

Patient connectionIndividual physical connections and / or metalparts intended for connection with the patient,which form (part of) an applied part.

Patient environmentVolumetric area in which a patient can come intocontact with medical equipment or contact canoccur between other persons touching medicalequipment and the patient, both intentional andunintentional. (see appendix D)

F-Type applied partApplied part which is electrically isolated fromearth and other parts of the medical equipment.i.e. floating. F-Type applied parts are either typeBF or type CF applied parts.

Type B applied partApplied Part complying with specifiedrequirements for protection against electricshock. Type B applied parts are those parts,which are usually Earth referenced. Type B arethose parts not suitable for direct cardiacapplication.

Type BF applied partF-Type applied part complying with a higher degreeof protection against electric shock than type Bapplied parts. Type BF applied parts are thoseparts not suitable for direct cardiac application.

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a) Measuring device b) Frequency characteristics

MD

+20

0

-20

-40

-60

10 102 103 104 105 106

Frequency (ƒ) in Hz

Rel

ativ

e m

agni

tud

ec) (d

b):

20 lo

gZ

(ƒ)

Z(ƒ

-10)

NOTE: The network and voltage measuring instrument above is replaced by the symbol in the following figures.a) Non-inductive componentsb) Impedance >> measuring impedance Zc) Z(ƒ) is the transfer impedance of the network, i.e. Vout/in, for a current frequency ƒ.

Z R2 C1

R1

V

Voltagemeasuringinstrumentb)

R1 = 10k Ω ±5%a)

R2 = 1k Ω ±5%a)

C1 = 0.015 µF ±5%

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Type CF applied partF-Type applied part complying with the highestdegree of protection against electric shock. TypeCF applied parts are those parts suitable fordirect cardiac application.

Class IEquipment protection against electric shock by(earthed) additional protection to basic insulationthrough means of connecting exposedconductive parts to the protective earth in thefixed wiring of the installation.

Class IIAlso referred to as double insulated. Equipmentprotection against electric shock is achieved byadditional protection to basic insulation throughmeans of supplementary insulation, there beingno provision for the connection of exposedmetalwork of the equipment to a protectiveconductor and no reliance upon precautions tobe taken in the fixed wiring of the installation.

Protective earthDedicated circuit intended to carry the fault andleakage current in class I equipment and to beconnected to the protective earth terminal.

Functional earthDedicated circuit intended to provide anelectrical screening and to be connected to afunctional earth terminal.

Line to earth voltageApplied voltage between the live wire and earthconductor, affecting the leakage current.

Leakage currentCurrent that is not functional.

Macro shock Non-invasive applied current which passes fromone side of the body to the other, typically handto hand or hand to foot, and therefore crossingthrough the heart.

Micro shockInvasively applied current which passes directlyacross the heart tissue.

NOTE: Class II equipment may be providedwith a functional Earth terminal or afunctional Earth conductor.

2.2 Symbols and MarkingsThe IEC 60601 defines the requirements forinformation / data to be present on the medicalequipment's nameplate, in order to form anunambiguous identification of the equipment.

Information must include; manufacturers name,model number, serial number, electricalrequirements etc.

The IEC 60601 standard refers to a large varietyof symbols for use on medical equipment,medical systems, accessories and other relatedparts. A full overview of the symbols used in IEC60601 is provided in table D1 of the standard.

For the purpose of this booklet, a selection of the most commonly used symbols is displayedopposite.

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2.3 Product LifecycleFor many years, ME equipment has been subjectto extensive approval processes from clinicaltrials, to type testing all the way through to end ofproduction line testing, to ensure it operatesproperly before leaving the factory. In addition,manufacturers recommend that regular electricalsafety and essential performance checks arecarried out to ensure there’s no risk of harmii tothe patient and operator once the device goesinto service.

Figure 5 - Safety stages through a productlifecycle

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Protective earth Earth reference point

Functional earth

Class II i.e. “Conformité Européene”

Type B applied part Defibrillation-proof type B applied part

Type BF applied part

Type CF applied part

Defibrillation-proof type BF applied part

Defibrillation-proof type CF applied part

DESIGN(IEC 60601)

TYPE TEST(IEC 60601)

END ofLINE TEST

OPERATORTRAINING

MAINTENANCE(IEC 62353)

REPAIR(IEC 62353)

ACCEPTANCE

DECOMMI-SSIONING

SAFETY

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3 IEC 60601

ME equipment must meet the designrequirements as set out by the IEC 60601 (aharmonised standard), which has been adoptedby all IEC member states. This sets out all thedesign criteria for producing equipment that iselectrically and mechanically safe, as well asplacing the onus on the manufacturer tounderstand how to reduce the risk of harm whenpatients and operators are exposed to theirmedical devices. All tests relating to the electricalsafety of ME equipment and devices can becategorised into two categories:

n MEANS OF OPERATOR PROTECTION(MOOP) - Means of protection for reducingthe risk of electric shock to persons other thanthe patient.

n MEANS OF PATIENT PROTECTION (MOPP)- Means of protection for reducing the risk ofelectric shock to the patient.

To ensure that ME equipment does not pose anelectrical hazard to the patient, or any otherperson, it is designed with sufficient levels ofisolation (dielectrics) to reduce the amount ofelectrical leakage current to an acceptable andsafe level - as low as 10µAiii.

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This is achieved by separating high electricalpotentials from any conductive parts, accessibleto the operator or patient. Dielectric strength isproven by applying a high voltage between highand low electrical potentials. However, this couldlead to a breakdown of the isolation and wouldtherefore be referred to as a destructive test.

A safer way to test the effectiveness of dielectricsis to perform a number of electrical leakage tests,such as leakage originating from the powersupply to the enclosure (MOOP) or protectiveearth wire (MOOP & MOPP) or even to thepatient connected parts (MOPP).

In IEC 60601, the test requirements for electricalleakage must be carried out under the worstpossible conditions to ensure absolute safety.This is achieved using an elevated mains at110% of the highest expected voltage (i.e. at240V mains this would mean testing at 264V).Preconditioning of the ME equipment is requiredprior to testing. Tests are done under normalcondition (no fault conditions), and including any one of the specific and relevant faultconditions.

Testing the protective earth circuit design forsufficient current carrying capabilities is achievedby stressing the design, passing a minimum testcurrent of 25 ampere RMS through the circuit fora minimum of 10 seconds. At these currentlevels, time duration and resistance values (<0.1Ohm internal equipment resistance), enoughenergy will be created to convert current intothermal heat. By observing the thermal profile ofa design, one can establish parts of the design

that might need to alter in order to reduce theelectrical resistance and thus the convertedenergy;

E = I² × R × t

Conducting such tests during the developmentand approval stages of a products life cycle,provides sufficient levels of confidence that theME equipment meets the design requirements ofIEC 60601. Once a design is approved formanufacturing and marketing, a subset of testswill suffice to ensure the product has been builtand assembled to the required product qualityand safety requirements. This subset of tests iscommonly referred to as routine tests and are notclearly defined in IEC 60601 thus can varybetween manufacturers and product designs. It’sfor this reason that the new IEC 62353:2014makes a recommendation that IEC 62353 canbe used during final testing and before putting apiece of ME equipment into service.

3.1 In-Service Test RequirementsIEC 60601-1 does not provide any guidance onroutine test requirements. This has led to differentinterpretations across the world on how to applyIEC 60601 to routine test scenarios.

Once a medical device leaves the factory, anumber of potential test scenarios arise,including:

Acceptance testing - also referred to as aninitial or reference test. This test is carried outprior to a new medical device being authorisedfor use and is undertaken to ensure correct and

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R&DDuring this stage a concept is subject to initial & clinical trials. Electronic and mechanicaldesign of the product (where applicable) must be in line with the IEC 60601 standard.

Type Testing

During this stage the product is expected to have completed the clinical trials and subjectto type testing is ready for marketing. The hardware and software of the product is verifiedagainst the design standards. When CE marking is obtained, the medical product can bemarketed.

ProductionDuring this stage the products are being assembled, tested and inspected for release intothe market place.

Acceptance

Once a medical device reaches the client, an acceptance test is performed. This test is toverify that the device is delivered in an acceptable condition, complete without any defaultsand available with all specified accessories. A performance and electrical safety test areoften completed as part of a reference for future maintenance.

PreventativeMaintenance

(Planned) Preventative Maintenance or PPM is a process whereby the device is subject toscheduled inspections and tests, in order to verify that the safety and operation are withinacceptable levels and criteria. This is referred to as pro-active maintenance.

RepairMaintenance

Should a device create a fault or require an upgrade, the device will be susceptible tofurther inspections and testing. This is referred to as re-active maintenance.

Decommissioning

At the end of a product lifecycle, is the decommissioning stage. The device, depending on its function and material content may be required to follow a set process (i.e. Anenvironmentally hazardous product will need to follow a recycling process. Under certainconditions, the device can be made available to other organisations in which a secondlifecycle can start at the acceptance stage.

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complete delivery. Acceptance testing is oftennot limited to an electrical safety test, with somebasic function tests also being applied to verifycorrect performance.

Routine testing - also referred to as plannedpreventative maintenance (PPM). This form oftesting is often conducted at fixed time intervals,which vary between types of equipment,manufacturers’ recommendations and riskassessment procedures undertaken by individualBME or medical physics departments. Routinetesting is not limited to safety testing and oftenincludes the verification of correct functionality.

After service & repair testing – this is carried-out following a repair or product upgrade and isoften part of a service carried out by in-hospitalmechanical or clinical engineering teams. In manycases, more rigorous electrical safety testing isneeded after the replacement of components orreconfiguration of medical devices.

4 Introduction to IEC 62353:2014

As its full name implies, IEC 62353 MedicalElectrical Equipment - recurrent test and testafter repair of ME equipment, defines therequirements for electrical safety testing ofmedical electrical (ME) equipment and systemsduring routine intervals.

Following the need for a unified approach toroutine testing, the first edition of IEC 62353brought together a set number of tests to allowits users to test the MOOP and MOPP dielectricintegrity via two distinct leakage current tests:

n EQUIPMENT LEAKAGE - Testing the totalleakage generated from the incoming mains tothe rest of the equipment (confirming integrityof the MOOP).

n APPLIED PART LEAKAGE - Testing thatfloating applied parts (BF&CF) remain at anacceptable floating level (confirming integrity ofthe MOPP).

In meeting this requirement the IEC 62353incorporates tests beyond those of type testing.Specifically, it seeks to provide a uniformed andunambiguous means of assessing the safety ofmedical equipment, whilst maintaining therelevance to IEC 60601-1 and minimising therisks to the person conducting the assessment.

Importantly, the IEC 62353 standard recognisesthat the laboratory conditions described in theIEC 60601, such as elevated mains, isolated TN(Terre Neutral) supply, temperature and humidityconditions cannot always be guaranteed whenin-service testing of medical devices isundertaken. More commonly, secondary earthconnections caused by data cables andsystems, provided measurement errors that cannow be overcome by IEC 62353. Another factorraised is that equipment could potentially bedamaged by applying type tests (IEC 60601)during in service testing and could thereforerepresent a potential danger to users.

One of the most significant changes to the 2014edition is the recommendation to test accordingto IEC 62353 at the final production line stageand also before equipment goes into service.This will allow recurrent testing to be directly

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comparable with factory tests, providing foreasier greater observation of any variations inleakage measurement. New in the IEC62353:2014 edition are a number of suggestedleakage tests that would isolate the touchleakage current or patient leakage current. Bothtests form part of the equipment leakage current.

However, if a manufacturer wants to provide aspecific measurement, the IEC 62353:2014 nowprovides guidance for these tests to beconducted in the informative section of thestandard – these might be considered when theequipment leakage values have changed fromprevious measurements. The 500V DC insulationtests in the 2014 edition have also been suppliedwith recommended pass/fail limits, taken frominternationally accepted practices for insulationtesting of electrical equipment. While insulationtests are optional, it’s always recommended tocheck with the equipment manufacturer if thiscan be conducted without damaging theequipment under test.

The strength of IEC 62353 enables those whocarry out testing to conduct a summary of tests onthe input of medical devices (equipment leakage)and on the output of the medical equipment(applied part leakage). As will become evidentfrom the following chapters, the time savingassociated with IEC 62353 will also allow for moretime to be spent on visual and functional testing.

4.1 How does IEC 62353 compare with IEC 60601?Although IEC 60601 is a type test standardgoverning the safety of the design and

manufacture of ME equipment, for decadesbiomed and clinical engineers have used the IEC60601 as the basis for regular testing or afterservice / repair of medical devices. Local variantsof IEC 60601 have also been adopted and usedas a basis for routine testing.

It is clear that most commonly used electricalsafety analysers will only provide means oftesting to a subset of tests described in IEC60601 and often exclude destructive tests suchas high voltage dielectric testing, constantcurrent 25A testing, SIP / SOP fault conditiontesting to aid portability and safety of theoperator.

So what are the main implications of testing toIEC 62353 and how does it differ from the verywell established and widely understoodrequirements of IEC 60601?

4.2 Technical ConsiderationsThe aim of IEC 62353 is to provide a uniformstandard that ensures safe practices andreduces the complexity of the current IEC60601-1 standard. All tests are based onleakage testing to IEC 60601, but a number ofaspects to improve safety and practicality havebeen removed.

The most significant changes are:

n No pre-conditioning of equipment under testn No elevated mains n No destructive testing n Testing under single fault condition only

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n Summarising leakage into input and output safety

n Testing at applied part level rather than at patient connection

n Different methods for conducting leakagetests subject to practicality

Many IEC 62353 tests are directly related to IEC60601 tests, which is shown in figure 6 below.

Figure 6: Comparing IEC 60601 with IEC 62353

4.3 Test FrequencyTo ensure safety and performance is managedthroughout the lifecycle of medical electricalequipment, manufacturers must specify theintervals for testing and inspecting their devices.The basis for this is risk assessment: thelikelihood of occurrence and severity of incorrectoperation. Consideration has to also be given tothe application of the product, frequency of use,the operational environment and operatorcompetency. IEC 62353:2014 recommendsfollowing the manufacturer’s instructions on testintervals. If this is not available, a test intervalbetween of between six to 36 months issuggested depending on risk assessment.

4.4 Vital Preparation Although IEC 62353 was first published in May2007, many companies and organisations arestill in the process of making changes to theirapproach to electrical safety testing. Toincorporate the IEC 62353 test philosophy intoany organisation requires necessary preparation.Options for choosing the correct set of tests,requires an understanding of the purpose andbenefits of using the different tests available.

Although the onus will inevitably fall on themanufacturers of medical devices to advise onappropriate in-service test procedures for theirown equipment, IEC 62353 clearly has an impacton medical service companies, biomed’s,medical physics, clinical engineering and othertechnical departments.

To help all those likely to be affected by theintroduction of IEC 62353 tests, a summary ofthe test requirements is provided within thisguidance booklet.

This IEC 62353 guidance booklet is intended forgeneral information only and cannot beconsidered a substitute for the full version of thestandard.

5 Visual Inspection

The process of visual inspection is not clearlydefined by IEC 60601, however visualinspections form a critical part of the generalsafety inspections during the functional life ofmedical equipment. In most cases, 70% of allfaults are detected during visual an inspection.

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A visual inspection is a relatively easy procedure,which is carried out to ensure that the MEequipment in use, still conforms to thespecifications released by the manufacturer andhas not suffered from any external damage and /or contamination.

The following inspections can be included:

n Housing / Enclosure - Look for damage,cracks etc.

n Integrity - Look for obstruction of moving parts, connector pins etc.

n Cabling (supply, applied parts etc.) Look for cuts, wrong connections etc.

n Fuse rating - check correct values after replacement.

n Markings and labelling - check the integrity of safety markings.

n Integrity of mechanical parts - check for any obstructions.

6 Earth Bond Testing

Protective earth conductors are designed toallow a safe and easy path (low resistance) forelectrical leakage and fault currents to flow,which allows the protective fuses or line currentmonitors (RCD’s, GFI’s) to operate and interruptthe supply voltage. This provides an importantmeans to reduce the risk of injury by electricshock and also stops the release of energy whichmay ultimately lead to fires.

In class I electrical equipment the protective earthconductor resistance needs to be of sufficientlylow value, in order to prevent the voltage on

external metal parts rising to a level where theshock potential presents a hazard to life.

Although many class I medical devices aresupplied with an earth reference point, most, ifnot all, medical devices require multiple earthbond tests to validate the connections ofadditional metal accessible parts on theenclosure.

A test current is applied between the earth pin ofthe mains supply plug and any accessible metalpart (including the earth reference point) via adedicated earth bond test lead (clip/probe).Figure 7 shows a representation of the earthbond test.

Figure 7 - Earth bond test in class I equipment

For fixed installations a point-to-point continuitymeasurement can be made by fitting a secondlead into the aux earth socket. The resistance isthen measured between the two leads.

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IEC 60601 IEC 62353Earth leakage Equipment leakage DIR/DIFEarth leakage SFC neutral Equipment leakage ALTEnclosure leakage SFC earth Equipment leakage DIR/DIFPatient leakage Equipment leakage (enclosure probe

disconnected)Mains on applied parts Applied part leakageMeasured values Some are calculatedOnly direct method Direct/differential and alternative

Ω

L

NPE

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The IEC 62353 requires a minimum test currentof 200mA, either AC or DC. When using a DCtest current, the resistance must be tested inboth polarities of the test current. The highestreading will determine the pass or fail result ofthis test.

The open circuit voltage of the current sourceshould not exceed 24V.

The test limits in IEC 62353 are set to:

100mΩ For a detachable power cable up to 3 metres

300mΩ For a class I device including powercable (not exceeding 3 metres)

500mΩ For a medical system consisting ofseveral medical and non-medicalpieces of equipment. See definitionof a medical system in IEC 60601-1:2005

Figure 8: Example of increased contactresistance in spring loaded contacts

6.1 Earth Bond Test ConsiderationsChecking the protective earth during routinetesting is different from that undertaken during thetype test approval. While testing at the designstage highlights the capacity of the design to copewith fault currents, the quality of the protectiveearth is more important during routine testing. It’simportant to remember that contact resistancecan be easily overlooked when using the required25A in IEC 60601 because high test currents cantemporarily repair poor mechanical contactsiv.

Contact resistance is made up of two components:1. Restriction resistance (where the conductive

cross section is reduced)2. Film resistance (the possible resistive layer

between the two conductive surfaces due tofilm oxidation, dust etc.)

Lower test currents, typically less than 8A RMS,are unable to temporarily overcome contactresistance (both film and restriction resistance)and thus highlight problems as a result of aging(increased restriction resistance due to softening

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of spring loaded force on the contacts typicallyfound in removable power cords, see figure 8).

High test currents (10A or more) tend to providea more constant reading (high precision) even ifthere is a potential constriction in the protectiveearth path. High test currents might also bedestructive to parts of the DUT which areconnected to the protective earth but have afunctional purpose (e.g. screening).

Therefore, IEC 62353 recommends thatprotective earth connections are tested with a200mA test current to highlight aging powercords although high readings could be as a resultof film resistance which can be removed.

Combining a high pre-pulse (to clean the filmresistance) and measuring with a low current toshow up any restriction resistance, is the mostaccurate way to determine the quality of theprotective earth path.

6.2 Precision vs AccuracyWhen performing an earth bond test, rememberthat accuracy must take precedence overprecision as having a consistently wrongmeasurement is precise but not very accurate.

Using a high test current might provide a higher precision (see figure 10), but would notnecessarily give you a more accuraterepresentation of the quality of the protectiveearth circuit due to its capability to temporarilyrepair constriction resistance.

Lower currents are not able to provide a falsepositive and are therefore fail-safe.

Low test current only (see figure 9) - Possiblelow accuracy and low precision as high readingscould be due to film or constriction resistance.

High test current only (see figure 10) - Possiblehigh precision but low accuracy as aging cableswith poor contact resistance will give the samereadings as a brand new good cable.

Low test current with high current pre-test(see figure 11) - Cleans film resistance, any highreadings would be down to poor contactresistance thus high accuracy and highprecision.

A separate white paper on high vs low testcurrents is available free of charge on our websiteat www.rigelmedical.com/rigel-downloads.

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Increased pressure(low resistance)

Low pressure applied(high resistance)

Figure 9: Low accuracy - low precision

Figure 10: Low accuracy -high precision

Figure 11: High accuracy -high precision

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7 Insulation Resistance Test

The risk of unacceptably high electrical faultcurrents can be minimised through designcriteria i.e. through effective levels of electricalinsulation/isolation. Such insulation can beachieved through physical spacing (creepageand clearance) of components, choice ofcomponents and dielectric materials, whileensuring the device operates properly.

The effectiveness of electrical insulation is testedthrough electrical leakage measurements (results in mA or µA) while the level of isolation isoften tested using a dielectric or insulation test.During a dielectric, or hipot test (furtherinformation available on hipot testers at,www.seaward.co.uk/hal-series), a high voltage(up to 4000V AC) is applied across different parts of the electronic design in order to stressthe dielectrics. Results are displayed in mA or µA - similar to that of leakage currentmeasurements. An insulation resistance testapplies a lower DC voltage, typically between250-500V DC, across different parts of theelectronic design. The results are displayed inMega ohms (MΩ).

Insulation resistance is normally checked byapplying 500V DC between:

n Input (live conductors, both phase and neutral,connected together) and enclosure (protectiveearth in class 1). See 7.1.

n Output (applied parts) and enclosure(protective earth in class 1). See 7.2.

n Input (phase and neutral) and output (appliedparts) for floating type applied parts (BF andCF). See 7.3.

The resistance is measured and then comparedwith the minimum acceptable value to assesspass or fail conditions, which can vary greatlydepending on design and test voltage variations.

With all measurements of insulation resistance,the appliance under test must have the powerswitch in the ‘ON’ position before performing thetest otherwise the test voltage does not passbeyond the mains switch, in which case only themains cord will be tested.

In addition, appliances fitted with electronicmains switches or RCD plugs cannot be testedin this manner because it is not possible to closethe mains switch (as they require mains to bepresent).

In some cases, sensitive electronic devices andparticularly older IT equipment, which does notcomply with EN60950, may be damaged by500V. However, in practice, this may not be asignificant issue as EN 60950 has been aroundlonger than most IT equipment currently in use.

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While the outcome of a 500V DC insulation testis quick and safe to do, in most cases it does notprovide a real indication of the effectiveness ofthe insulation in modern medical devices or theexpected leakage values that may beexperienced during normal or typical operation.This is due to the increased use of switch modepower supplies that may indicate very high DCinsulation resistance (>100MΩ), when measuredwith AC indicate high leakage. This is due to thegreater influence of capacitive and inductiveleakage experienced in these devices rather thanresistive leakage as in a heating element.

Infinity readings are common when performingDC insulation tests and provide no information asto whether the unit was actually switched on oroff. This makes the test results meaningless froma safety point of view.

It is a matter of debate as to whether a 50 MΩ(higher) result is ‘safer’ than a 10 MΩ (lower)result, considering the equipment has beenexposed to a voltage it was not designed tooperate at. Furthermore, the 50 MΩ (higher)device might have been designed to measure100 MΩ and has thus lost 50% of its insulationlevel. This could lead to higher leakage currentsand unsafe conditions.

Finally, in some electrical equipment,components connected to the live/neutralconductors for EMC filtering or surge protectioncan significantly influence the measurement,indicating an erroneous failure of the test.

On the plus side, the insulation resistance test isrelatively quick and easy to perform, which is whyit is probably the most widely used.

7.1 Insulation Resistance EUT to EarthThis test is used to verify that the mains parts areadequately insulated from earth (class I) or theenclosure (class II). Figures 12 and 13 below,show a representation of the insulation test.

Figure 12: Insulation test mains parts to protective earth, class I

Figure 13: Insulation test mains parts tonon-earthed accessible conductive parts,class I and II

During this test, 500V D.C. is applied betweenthe earth pin and both the live and neutralpins of the appliance mains supply plug.

I nnova t ing Togethe r

L

N

PE

MP AP

L

N

PE

MP AP

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For both class I and class II appliances plug the DUT into the safety analyser. Class IIequipment requires an auxiliary lead to beconnected to the enclosure of the equipment.This can be done by wrapping the enclosure inaluminium foil and connecting it to the auxiliarylead via a crocodile clip.

7.2 Insulation Resistance Applied PartsThis test is used to verify that the applied partsare adequately insulated from earth (class I) orthe enclosure (class II). This test is applicable toclass I and class II, BF and CF equipment only.Figure 14 and figure 15 show a representation ofthis insulation test.

Figure 14: Insulation test applied parts to protective earth, class I

Figure 15: Insulation test applied parts tonon-earthed accessible conductive parts,class I and II

During this test, 500V D.C. is applied betweenthe earth pin (class I) or the enclosure (classII) and all the applied parts combined.

For both class I and class II appliances, connectthe patient connections or applied parts to thecorresponding terminals of your safety analyser.For class I equipment, plug the mains plug intothe safety analyser. Class II equipment requiresan auxiliary lead to be connected to theenclosure of the equipment. This can be done bywrapping the enclosure in aluminium foil andconnecting the auxiliary lead via an alligator clip.

7.3 Insulation Resistance Applied Parts to MainsThis test is used to verify that the applied partsare adequately insulated from the mains partsand is applicable to class I and class II, BF andCF equipment only. Figure 16 show arepresentation of the applied parts to mainsinsulation test.

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Figure 16: Insulation test mains parts to applied parts, class I and II

During this test, 500V D.C. is applied betweenall the applied parts combined and both thelive and neutral pins of the appliance mainssupply plug.

For both class I and class II appliances, connectthe patient connections or applied parts to thecorresponding terminals of your safety analyserand connect the mains plug to the safetyanalyser.

7.4 Insulation Test Pass – Fail LimitsAlthough ultimately the pass / fail limits orexpected minimum values for this test must beadvised by the manufacturer of the equipment,the IEC 62353 does provide a list of commonlyaccepted values:

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L

NPE

MP AP

AP1

AP2

L

NPE

MP AP

AP1

AP2

L

NPE

MP AP

AP1

AP2

BBF, CF

Figure Class B BF CF

Figure 12 I ≥ 2 MΩ ≥ 2 MΩ ≥ 2 MΩ

Figure 13 I and II ≥ 7 MΩ ≥ 7 MΩ ≥ 7 MΩ

Figure 14 I and II ≥ 70 MΩ ≥ 70 MΩ ≥ 70 MΩ

Figure 15 I and II ≥ 70 MΩ ≥ 70 MΩ ≥ 70 MΩ

Figure 16 I ≥ 2 MΩ ≥ 70 MΩ ≥ 70 MΩ

Figure 16 II ≥ 7 MΩ ≥ 70 MΩ ≥ 70 MΩ

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8 IEC 62353 Leakage Measurements

As covered in 1.2, it is the level of electricalcurrent rather than level of voltage which is thecriteria for safety due to the impact of electricalcurrents on the human tissues. Small amounts ofcurrent which are undetectable by sensation canhave a significant impact on our safety.

IEC 62353 defines two different kinds of leakagecurrent tests:

Equipment leakage current - total leakagederiving from the power supply to earth via theapplied parts and enclosure, see 8.2.

Applied part leakage current - leakage currentflowing from an applied part to the enclosure orearth as a result of an external voltage on theapplied part, see 8.3.

8.1 Method CharacteristicsTo ensure that a valid leakage measurement canbe obtained, the IEC 62353 describes thefollowing methods:

Direct Leakage - measurement of leakagecurrent via a measuring device, placed directly inthe path of the leakage current, see 8.1.1.

Differential Leakage - measuring the imbalancebetween current in the Live conductor and theneutral conductor as a result of leakage current,see 8.1.2.

Alternative Method - measurement of leakagewhen mains voltage is both on the live andneutral wire, see 8.1.3.

8.1.1 Direct LeakageThe direct leakage method is identical to themethod used in the IEC 60601-1 standard;measuring the true leakage through a bodymodel (measuring device) to earth.

Benefits:n Means of measuring both AC and DC leakage

current.n Highest accuracy compared to other

methods.n Potential leakage through a human body via

measuring device.n Direct comparison with measurements made

in accordance with IEC 60601-1.

To consider:n The 1kΩ resistor forming the measuring device

is interrupting the low resistance protectiveearth conductor, thus causing a potentialhazard when testing faulty equipment.

n Secondary earth path(s) could lead to zerocurrent readings, see 8.4.

n A difference in polarity of the live and neutralconductors might alter the leakage readings,as such leakage measurements must be donein each polarity of mains supply.

n A TN (terre – neutral) system is required toensure that the measurements are done atmaximum live to earth voltage. Any voltagebetween neutral and earth might result in alower reading, potentially passing faultyequipment, see 8.5.

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8.1.2 Differential MethodThe differential leakage method measures theleakage current as a result of an imbalance incurrent between the live conductor and theneutral conductor.

The principle of the differential leakagemeasurement is based on induction hence, thismethod is susceptible to external magnetic fieldsand high load currents. As current passesthrough the live wire in one direction, the currentin the natural wire travels in the oppositedirection. Each current produces a magnetic fieldin opposite directions and directly proportional tothe strength of current. See figure 17.

Figure 17: Opposite magnetic fields in live and neutral wire

The current in the live wire carries both thefunctional current and the leakage currentwhereby the current in the neutral wire containsonly the functional current. By subtracting bothcurrents, you end up with the leakage current.

This is done in practise by passing both live andneutral wires through a current transformer (CT).The live and neutral wires act as the primarywindings whereas the CT acts as the secondarywinding. The net magnetic field in the primarywire is equal to the leakage current as the neutral“field” cancels all but the leakage current fromthe live wire. The current being inducted in theCT is equal to the leakage current.

Potential secondary earth connections areincluded in the total measurement and as such,the EUT is not required to be isolated from realEarth.

Benefits:n The measurements are not influenced by

secondary earth connections.n It measures the total equipment leakage

current.n The measuring device (1kΩ resistor) is no

longer in series with the earth conductor,providing a low resistance protective earth andthus is a safer practise compared to the directmethod.

Neutral conductor

Live conductor

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To consider:n The differential leakage measurement is less

suitable to accurately measure lower leakagecurrents (<100µA).

n The measurements can be influenced byexternal magnetic fields or the analyser’s owninternal magnetic fields.

n The measurements can be influenced by highcurrent consumption of the DUT.

n The measurements have limited frequencyresponse.

n A difference in polarity of the live and neutralconductors might alter the leakage readings;as such leakage measurements must be donein each polarity of mains supply.

n Both direct and alternative methods providehigher accuracy and broader frequencyresponse which is required for measuringtrends in low leakage conditions.

8.1.3 Alternative MethodThe alternative method is in effect similar to adielectric strength test at mains potential, or aninsulation test at AC voltage, using a currentlimited voltage source (test voltage) at mainsfrequency. The maximum short circuit current islimited to 3.5mA through a current limitingresistor of 66kΩ, see figure 18.

The live and neutral conductors are shortedtogether and the test voltage is applied between the mains parts and other parts of theequipment.

The current limiting resistor of 66kΩ will result inan internal voltage drop when a fault current isflowing. Therefore, the applied test voltage willdecrease when the leakage current increases.

To reflect testing at mains voltage, the measuredleakage current is scaled in proportion to theactual output voltage.

In the example below, a resistance (37kΩ) hasbeen allocated to an applied part type BF. Thetotal resistance connected to the mains voltageis 103kΩ which results in a fault current of2.23mA, measured at a voltage of only 83V overthe applied part.

Figure 18: Example of current limitedmains supply during alternative leakage

IEC 62353 requires you to scale the measuredleakage value up, equivalent to having 230V overthe applied part;

(230V / 83V) x 2.2 mA = 6 mA

The safety analyser will display 6mA despite onlymeasuring 2.23mA. In this approach, it ispossible to display high (calculated) leakagecurrents without actually being exposed todangerous currents, making the alternativeleakage current safe to use when high faultcurrents are expected.

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Benefits:n As live and neutral are combined, the mains

polarity has no influence. Only onemeasurement is required.

n The DUT is disconnected from mains thusproviding a high level of safety for the testengineer.

n TN-System is not required due to mains freeapplication.

n Measurements are not influenced bysecondary earth connections.

n Measurements are highly repeatable andprovide a good indication of deterioration inthe dielectrics of the medical device undertest.

To consider:n Equipment will not be activated thus,

preventing the measurement of actual leakagecurrents on equipment with switched circuits.

8.2 Equipment LeakageEquipment leakage current - total leakagederiving from the power supply to earth via theapplied parts and enclosure. The equipmentleakage test is applicable to both class I and II, B,BF and CF equipment.

Leakage measurements to IEC 62353 are doneusing the RMS value instead of the separate ACand DC values used in the IEC 60601-1standard.

The IEC 62353 specifies three different methodsfor measuring the equipment leakage current:

n Direct methodn Differential methodn Alternative method

8.2.1 Equipment Leakage Direct Method The direct method is identical to the methodused in the IEC 60601-1.

Figure 19 and figure 20 show a representation ofthe direct method.

Figure 19: Equipment leakage direct - class I

Figure 20: Equipment leakage direct – class II

RI = 66kΩ

83 VU=230V50HZ ±2.2 mA L

NPE

MP AP

MD

L(N)

N(L)

L

N

MP AP

MD

L(N)

N(L)

PE

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The DUT must be positioned floating to avoidsecondary earth connections influencing themeasuring process.

All applied parts (B, BF & CF) and earthed (e.g.enclosure class I) and non-earthed accessibleconductive parts or non-conductive accessibleparts (enclosure class II) are grouped togetherand connected to the earth via the 1kΩmeasuring device (body model).

The 1kΩ measuring device (MD - equivalent to that used in the IEC 60601 standard –

see 1.3) is positioned in the leakage return path to earth.

The test is conducted with the protective earthconnection ‘interrupted’, to ensure themeasurements are carried out under the worstpossible conditions. As such, any earth leakagecurrent will be measured as part of the enclosure(or touch) leakage.

Measurements are done in both polarities of theincoming mains with the protective earth to theEUT interrupted.

8.2.2 Equipment Leakage Differential MethodFigure 21 and figure 22 show a representation ofthe differential method.

Figure 21: Equipment leakage differential - class I

Figure 22: Equipment leakage differential – class II

Potential secondary earth connections areincluded in the total measurement and as such,the DUT is not required to be positioned isolatedfrom earth.

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All applied parts (B / BF & CF), earthed (e.g.enclosure class I) and non-earthed accessibleconductive parts or non-conductive accessibleparts (enclosure Class II) are grouped togetherand connected to earth to allow the differentialcircuit to measure the total leakage current.

Unlike the direct method, the differential methoddoes not measure the earth conductor via thestandard IEC 60601 body model. The MD is partof a differential current measurement betweenthe live and neutral conductors. The frequencyresponse of the measurement shall be similar tothe body model used in the IEC 60601.

The test is conducted with the protective earthconnection closed for protection of the user.

Measurements are done in both polarities of theincoming mains with the protective earth to theEUT interrupted.

Low leakage currents of less than 75µA aredifficult to measure using the differential leakagemethod. As such the differential leakage methodis unsuitable when measuring conductive un-earthed parts and in instances where leakagesare expected to be below 75µA.

8.2.3 Equipment Leakage Alternative MethodThis method is in fact similar to a dielectric testbetween the mains parts and all accessible parts(conductive and non-conductive) including theapplied parts connected together. Figure 23 andfigure 24 show a representation of the alternativemethod.

Figure 23: Equipment leakage alternative - class I

Current in µA (RMS)APPLIED PART

B BF CF

Equipment leakage – direct or differential method

Class I equipmentClass II equipment (touch current)

500µA100µA

500µA100µA

500µA100µA

For mobile x-ray generators 2000 µA

Current in µA (RMS)APPLIED PART

B BF CF

Equipment leakage – direct or differential method

Class I equipmentClass II equipment (touch current)

500µA100µA

500µA100µA

500µA100µA

For mobile x-ray generators 2000 µA

L

N

MP APL(N)

N(L)

PE

M

L

N

MP APL(N)

N(L)

PE

M

MP AP

MD

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Figure 24: Equipment leakage alternative – class II

The test is performed using a current limited(3.5mA) mains potential sinusoidal 50Hz signal(60Hz where this is the mains frequency).

As live and neutral are shortened, the DUT is notdirectly connected to the mains potential. As

such, mains reversal is not applicable and theEUT is not required to be positioned isolatedfrom earth.

All applied parts, and earthed (e.g. enclosureclass I) and non-earthed accessible conductiveparts or non-conductive accessible parts(enclosure class II) are grouped together andconnected to the mains parts via the 1kΩmeasuring device (body model) and voltage source.

The 1kΩ measuring device (equivalent to thatused in the IEC 60601 standard – see 1.3) ispositioned directly after the voltage source.

The test is conducted with the protective earthconnection closed to protect the user.

8.3 Applied Part LeakageThe applied part leakage test measures the totalleakage deriving from the combined patientconnections within an applied art to earth and anyconductive or non conductive parts on theenclosure (either connected or isolated from earth)under the fault condition mains on the applied parts.

The applied part leakage test is applicable tofloating type (BF & CF) applied parts only eitherclass I or II.

All patient connections of a single function withinan applied part shall be connected together (BF& CF) and measured one at the time.

Applied parts (and patient connections) are notpart of the measurement and shall be left floatingi.e. not connected to real earth.

The test is conducted by applying a currentlimited (3.5mA) mains potential sinusoidal 50Hzsignal (60Hz where this is the mains frequency)

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between the applied part, the enclosure andearth connection of the EUT that is connected toreal earth.

Leakage measurements to IEC 62353 are doneusing the RMS value instead of the separate ACand DC values used in the IEC 60601-1standard.

The IEC 62353 / applied part leakage can beperformed in two different methods:

n Direct methodn Alternative method

8.3.1 Applied Part Leakage Direct MethodFigure 25 and figure 26 show a representation ofthe direct method.

Figure 25: Applied part leakage direct - class I

Figure 26: Applied part leakage direct – class II

The DUT must be positioned floating to avoidsecondary earth connections influencing themeasuring process.

All floating type patient connections in eachapplied part (BF & CF) are connected together.Each Individual applied part is measured in turnand grouped together with all earthed (e.g.enclosure class I) and non-earthed accessibleconductive parts or non-conductive accessibleparts (enclosure class II) and connected to earthvia the 1kΩ measuring device (body model).

Applied parts and patient connections not part ofthe measurement shall be left floating.

The 1kΩ measuring device (MD - equivalent tothat used in the IEC 60601 standard – see 1.3) is positioned between the applied part andvoltage source.

MP AP

MD

Current in µA (RMS)APPLIED PART

B BF CF

Equipment leakage – alternative method

Class I equipmentClass II equipment

1000µA500µA

1000µA500µA

1000µA500µA

For mobile x-ray generators 5000 µAL

N

MP APL(N)

N(L)

PE MD

AP1

AP2

L

N

MP APL(N)

N(L)

PE MD

AP1

AP2

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The test is conducted with the protective earthconnection closed for protection of the user.

Measurements are done in both polarities of theincoming mains with the protective earth to theEUT interrupted.

Warning: This applied part direct leakage test issimilar to that of the F-Type leakage testaccording to IEC 60601, using an equivalentcurrent limited voltage source to produce the

mains potential. Both sources depend on acurrent limiting resistor which could cause asignificant voltage drop. See figure 18.

Unlike the IEC 60601-1 requirements, thevoltage drop caused by the current limitingresistor is compensated for in the IEC 62353thus, potentially resulting in a higher reading thanthe typical IEC 60601-1 F-type test. Please referto the manufacturer’s recommendations.

8.3.2 Applied Part Leakage Alternative MethodThis method is in fact similar to a dielectric testbetween the applied part, and all mains parts,EUT earth and enclosure all connected together.Figures 27 and 28 show a representation of thealternative method.

Figure 27: Applied part leakage alternative – class I

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Figure 28: Applied part leakage alternative – class II

As live and neutral are shortened, the DUT is notdirectly connected to the mains potential. Assuch, mains reversal is not applicable and theEUT is not required to be positioned isolatedfrom earth.

All floating type patient connections in each appliedpart (BF & CF) are connected together. Eachindividual applied part is measured in turn andconnected via the 1kΩ measuring device (bodymodel) to the voltage source and earthed (e.g.enclosure class I) and non-earthed accessibleconductive parts or non-conductive accessibleparts (enclosure class II) grouped together.

Applied parts and patient connections not part ofthe measurement shall be left floating.

The 1kΩ measuring device (MD - equivalent tothat used in the IEC 60601 standard – see 1.3) is positioned between the applied part andvoltage source.

The test is conducted with the protective earthconnection closed to protect the user.

8.4 Secondary Earth ProblemsDue to the fact that electrical currents follow thepath of least resistance (much like water does), itis important to realise that secondary earth pathconnections could influence the measurementsof leakage currents.

Secondary connections are typical with:

n Equipment bolted to steel reinforced concretefloor (e.g. dentist chairs, MRI)

n Equipment connected to gas or water supplyn Equipment that is part of a medical electrical

systemn Equipment connected to PC / printer

Current in µA (RMS)APPLIED PART

B BF CF

Applied part leakage current – direct method (a.c.)

Class I & II N/A 5000µA 50µA

For defibrillation paddles class CF N/A 100µA

MP AP

MD

AP1

AP2

MP AP

MD

AP1

AP2

Current in µA (RMS)APPLIED PART

B BF CF

Applied part leakage current – alternative method (a.c.)

Class I & II N/A 5000µA 50µA

For defibrillation paddles class CF N/A N/A 100µA

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Compared to the 1kΩ resistance of the bodymodel, a secondary earth path is substantiallylower. As such, electrical currents are mostlyflowing down the secondary earth path, awayfrom the safety analyser, as shown in figure 29,which represents an example of a secondaryearth connection via a data cable.

Figure 29: Example showing leakagecurrent flowing away via a secondary earth connection

This will result in a zero reading on the safetyanalyser and could potentially pass a dangerousmedical device.

In case a secondary earth path exists, the Rigel288 / 62353 will provide the user with an errormessage as shown in figure 30.

Figure 30: Secondary earth path errormessage on Rigel 288 / 62353

If the secondary earth path can’t be removed,one should revert to the differential leakagemethod which is capable of measuring the totalleakage even when a secondary earth pathexists. This is because the differential leakagemethod does not rely on a 1kΩ body model. Seefigure 31.

Figure 31: Measuring leakage current withsecondary earth using differential method

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8.5 Live to Earth VoltageDuring equipment leakage measurements (direct and differential), the live to earth voltagecan have a direct impact on the leakagemeasurement. In general, the smaller the live toearth voltage, the lower the leakage current toearth (leakage current flows from a high – live toa low – earth potential).

Measurements under a TN (terre – neutral)system ensure the live to earth voltage is equal to the line voltage (between live and neutral). This gives the highest possible leakage outcome, see figure 32. If the earth potential differs fromthe neutral potential, the live to earth voltage willbe reduced, and result in a lower leakage value,see figure 33.

Figure 32: Leakage measurement on a TN system

Figure 33: Leakage measurement on a IT system

Leakage current measurements on an IT(isolated terre) are limited to isolation levels of thesupply system. In this case, no valid leakagemeasurement is possible unless the safetyanalyser is able to produce an internal earth athalf the line voltage, like the Rigel 288. It is alsopossible to test using the equipment leakageusing the alternative method which does not relyon the incoming mains configuration.

AP

Display

MD

L

N

1000Ω<5Ω

AP

Display

L

N

<5Ω

Differential

N

E

L

230V

230V

0V

0V

E

N

L

130V

230V

0V

100V

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The Rigel 288 and 62353 are able to provide anautomatic warning to the user in case the supplyconfiguration differs from an TN configuration.

Figure 34: Automatic mains configurationwarning on Rigel 288 / 62353

9 Record Keeping

Overall, risk assessment and the creation of riskmanagement files has become a growing featureof routine safety testing decisions, with differentorganisations and departments drawing-upindividual plans to deal with specific safetyhazards. Comparison with previous andexpected test results will therefore allow you tomonitor deterioration of the device under testand can prevent potential failure before a faultoccurs.

9.1 Comparing DataTesting to IEC 62353 has reduced the time takento conduct an electrical safety test – down fromfive minutes to less than 15 secondsv in somecases. What’s more, a direct outcome ofreducing the amount of individual tests is that

results can be easily compared against previousreadings: tests in different polarities of theincoming mains rarely result in significantdifference in readings, so under IEC 62353 onlyan equipment leakage and applied part leakagevalue has to be observed, making comparisoneasy and quick. Comparing data also makes itpossible to monitor leakage against expectedvalues rather than the test limits in the IEC62353.

Electrical safety testing is only part of the totalservice carried out on medical equipment. Oncethe safety is accessed, the functionality is verifiedand recorded before the equipment is returnedfor use on patients.

Rigel Medical has produced a range ofinformative booklets that cover the performanceverification of; vital signs monitors, infusionpumps and electro surgical generators.

Please visit www.rigelmedical.com/rigel-downloadsto request your free copy.

To ensure proper record keeping is maintained itis important to provide a procedure in which datais collected regarding:

n Inspection daten Visual inspectionn Electrical safetyn Functional testingn Next inspection date

The IEC 62353 provides a guideline in collectingsuch information with the purpose of developing

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consistency in data collection and management.By doing so, trends can be monitored to benefit:

n Identifying common faultsn Detect component deterioration (preventative

maintenance)n Develop efficient re-test periods

Rigel Medical has developed Med-eBase, a testsolutions software package to automate thegeneration of test reports including visualinspection, electrical safety and performancetesting. An example of such test templates isprovided in appendix E.

Going forward, determining the appropriatelevels of both electrical and functional testing willbe central to the introduction of cost effective yetreliable preventative maintenance campaigns.

10 Conclusion

Electrical safety testing of medical electronicdevices remains a crucial part of the overallsafety validation of medical devices and requiresspecialised test equipment.

The IEC 62353 standard will provide;

n A globally recognised approached to safetytesting

n Development tools for safer and more suitabletest protocols

n Significant time savings during routine safetytesting

n An easy method to analyse results againstprevious measurements

n A method of record keeping and maintenanceprocedures

The strength of IEC 62353 is that it allows thosewho carry out the test to conduct a summary oftests on the input of medical devices (equipmentleakage) and on the output of the medicalequipment (applied part leakage). Uniformity intest procedures, time (and cost) savings and asimplified means of analysing test data areamong other significant benefitsvi for those whohave made the transition to testing inaccordance with IEC 62353. Time savingassociated with IEC 62353 will also allow formore time on visual and functional testing, thusleading to improved patient safety.

Additional test setups such as the differentialmethod and alternative method give the user avalid measurement when circumstances mightnot allow for a valid test measurement under IEC60601 (direct method).

When choosing your future electrical safetyanalyser, ensure that it can be used to test inaccordance with the IEC 62353 requirementsand secondly that your analyser will enable youto accurately and repeatedly produce the resultsyou require.

10.1 Considerations and Recommendations1. Ensure that the operator of the safety

analyser is properly trained on both the safetyanalyser as well as the device under test toensure that valid measurements are takenand understood, to prevent unneccessarydanger during the safety test.

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2. Always ensure that the device under testdoes not pose any danger to the user and /or people within the vicinity to the safety test.(e.g. moving parts, open conductors, livecomponents, heat etc.).

3. Ensure that leakage measurements areperformed whilst the equipment is in fulloperation mode, including its sub-systems orcomponents, unless the alternative method isbeing carried out.

4. Appreciate that secondary earth connectionswill lead to invalid measurements. Understandhow to spot secondary earth connections orbenefit from the automatic warning feature onthe Rigel 288 / 62353.

5. Ensure accuracy and repeatability of leakagemeasurement readings (some manufacturersmight specify full scale accuracy which will effectthe accuracy of low leakage measurements).

6. Ensure that contact resistance is taken intoaccount when measuring the earth continuity atlow currents (<8A). Contact resistance caninfluence the readings and cause unnecessaryfailures of the device under test. Visitwww.rigelmedical.com/rigel-downloads for yourfree application note on low current testing.

7. When determining the correct means oftesting aspecific piece of medical equipment,ensure that the chosen safety test proceduresare applicable to the device under test andare clearly documented for future use.

Rigel Medical offers a range of test equipment in line with the IEC 62353 and IEC 60601requirements. Please visit our websitewww.rigelmedical.com/products for a full overviewof our product offering or register online for our freenewsletter on future product releases and productinnovations (visit www.rigelmedical.com/news).

For further questions or comments relating to thisbooklet or on the Rigel Medical product offering,please contact John Backes via email [email protected].

You can follow the Seaward Group on:

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Appendix APass / Fail Limits of IEC 62353

Current in µA (RMS)APPLIED PART

Type B Type BF Type CF

Equipment leakage – alternative method

Class I equipmentClass II equipment

1000µA500µA

1000µA500µA

1000µA500µA

For mobile x-ray generators 5000 µA

Equipment leakage – direct or differential method

Class I equipmentClass II equipment (touch current)

500µA100µA

500µA100µA

500µA100µA

For mobile x-ray generators 2000 µA

Applied part leakage current – alternative method (AC)

Class I & II N/A 5000µA 50µA

For defibrillation paddles class CF N/A N/A 100µA

Applied part leakage current – direct method (AC)

Class I & II N/A 5000µA 50µA

For defibrillation paddles class CF N/A N/A 100µA

NOTE 1 This IEC 62353 standard does not provide measuring methods and allowable valuesfor equipment producing DC leakage currents. In such a case the manufacturer should give information in accompanying documents.

NOTE 2 Particular standards may allow different values of leakage current. For a list of particular standards, please refer to Appendix C.

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IEC 60601-1 ed3.1Medical electrical equipment - Part 1: General requirements for basic safety andessential performance

IEC 60601-1-2 ed4.0Medical electrical equipment - Part 1-2: General requirements for basic safety andessential performance - Collateral Standard: Electromagnetic disturbances -Requirements and tests

IEC 60601-1-3 ed2.1Medical electrical equipment - Part 1-3: General requirements for basic safety and essential performance - Collateral Standard: Radiation protection in diagnostic X-ray equipment

IEC 60601-1-6 ed3.1Medical electrical equipment - Part 1-6: General requirements for basic safety andessential performance - Collateral standard: Usability

IEC 60601-1-8 ed2.1

Medical electrical equipment - Part 1-8: General requirements for basic safety andessential performance - Collateral Standard: General requirements, tests andguidance for alarm systems in medical electrical equipment and medical electrical systems

IEC 60601-1-9 ed1.1Medical electrical equipment - Part 1-9: General requirements for basic safety andessential performance - Collateral Standard: Requirements for environmentallyconscious design

IEC 60601-1-10 ed1.1Medical electrical equipment - Part 1-10: General requirements for basic safety andessential performance - Collateral Standard: Requirements for the development ofphysiologic closed-loop controllers

IEC 60601-1-11 ed1.0Medical electrical equipment - Part 1-11: General requirements for basic safety andessential performance - Collateral Standard: Requirements for medical electricalequipment and medical electrical systems used in the home healthcare environment

IEC 60601-1-12 ed1.0

Medical electrical equipment - Part 1-12: General requirements for basic safety andessential performance - Collateral Standard: Requirements for medical electricalequipment and medical electrical systems intended for use in the emergency medicalservices environment

IEC 60601-2-1 ed3.1Medical electrical equipment - Part 2-1: Particular requirements for the basic safetyand essential performance of electron accelerators in the range 1 MeV to 50 MeV

IEC 60601-2-2 ed5.0Medical electrical equipment - Part 2-2: Particular requirements for the basic safetyand essential performance of high frequency surgical equipment and high frequencysurgical accessories

IEC 60601-2-3 ed3.0Medical electrical equipment - Part 2-3: Particular requirements for the basic safetyand essential performance of short-wave therapy equipment

IEC 60601-2-4 ed3.0Medical electrical equipment - Part 2-4: Particular requirements for the basic safetyand essential performance of cardiac defibrillators

IEC 60601-2-5 ed3.0Medical electrical equipment - Part 2-5: Particular requirements for the basic safetyand essential performance of ultrasonic physiotherapy equipment

IEC 60601-2-6 ed2.0Medical electrical equipment - Part 2-6: Particular requirements for the basic safetyand essential performance of microwave therapy equipment

IEC 60601-2-8 ed2.0Medical electrical equipment - Part 2-8: Particular requirements for basic safety andessential performance of therapeutic X-ray equipment operating in the range 10 kV to 1 MV

IEC 60601-2-10 ed2.0Medical electrical equipment - Part 2-10: Particular requirements for the basic safetyand essential performance of nerve and muscle stimulators

IEC 60601-2-11 ed3.0Medical electrical equipment - Part 2-11: Particular requirements for the basic safetyand essential performance of gamma beam therapy equipment

IEC 60601-2-16 ed4.0Medical electrical equipment - Part 2-16: Particular requirements for basic safety and essential performance of haemodialysis, haemodiafiltration and haemofiltrationequipment

IEC 60601-2-17 ed3.0Medical electrical equipment - Part 2-17: Particular requirements for the basic safety and essential performance of automatically-controlled brachytherapyafterloading equipment

IEC 60601-2-18 ed3.0Medical electrical equipment - Part 2-18: Particular requirements for the basic safetyand essential performance of endoscopic equipment

IEC 60601-2-19 ed2.0Medical electrical equipment - Part 2-19: Particular requirements for the basic safetyand essential performance of infant incubators

IEC 60601-2-20 ed2.0Medical electrical equipment - Part 2-20: Particular requirements for the basic safetyand essential performance of infant transport incubators

IEC 60601-2-21 ed2.0Medical electrical equipment - Part 2-21: Particular requirements for the basic safetyand essential performance of infant radiant warmers

IEC 60601-2-22 ed3.1Medical electrical equipment - Part 2-22: Particular requirements for basic safety and essential performance of surgical, cosmetic, therapeutic and diagnostic laser equipment

IEC 60601-2-23 ed3.0Medical electrical equipment - Part 2-23: Particular requirements for the basic safetyand essential performance of transcutaneous partial pressure monitoring equipment

Appendix BIEC 60601-1 Collateral Standards (© IEC, http://webstore.iec.ch/?ref=menu)

Appendix CIEC 60601-2 Particulars Standards (© IEC Geneva, Switzerland)

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IEC 60601-2-24 ed2.0Medical electrical equipment - Part 2-24: Particular requirements for the basic safetyand essential performance of infusion pumps and controllers

IEC 60601-2-25 ed2.0Medical electrical equipment - Part 2-25: Particular requirements for the basic safetyand essential performance of electrocardiographs

IEC 60601-2-26 ed3.0Medical electrical equipment - Part 2-26: Particular requirements for the basic safetyand essential performance of electroencephalographs

IEC 60601-2-27 ed3.0Medical electrical equipment - Part 2-27: Particular requirements for the basic safetyand essential performance of electrocardiographic monitoring equipment

IEC 60601-2-28 ed2.0Medical electrical equipment - Part 2-28: Particular requirements for the basic safetyand essential performance of X-ray tube assemblies for medical diagnosis

IEC 60601-2-29 ed3.0Medical electrical equipment - Part 2-29: Particular requirements for the basic safetyand essential performance of radiotherapy simulators

IEC 60601-2-31 ed2.1Medical electrical equipment - Part 2-31: Particular requirements for the basic safetyand essential performance of external cardiac pacemakers with internal power source

IEC 60601-2-33 ed3.1Medical electrical equipment - Part 2-33: Particular requirements for the basic safetyand essential performance of magnetic resonance equipment for medical diagnosis

IEC 60601-2-34 ed3.0Medical electrical equipment - Part 2-34: Particular requirements for the basic safetyand essential performance of invasive blood pressure monitoring equipment

IEC 60601-2-36 ed2.0Medical electrical equipment - Part 2-36: Particular requirements for the basic safetyand essential performance of equipment for extra-corporeally induced lithotripsy

IEC 60601-2-37 ed2.0Medical electrical equipment - Part 2-37: Particular requirements for the basic safetyand essential performance of ultrasonic medical diagnostic and monitoring equipment

IEC 60601-2-39 ed2.0Medical electrical equipment - Part 2-39: Particular requirements for basic safety andessential performance of peritoneal dialysis equipment

IEC 60601-2-40 ed1.0 Medical electrical equipment - Part 2-40: Particular requirements for the safety ofelectromyography and evoked response equipment

IEC 60601-2-41 ed2.1Medical electrical equipment - Part 2-41: Particular requirements for the basic safetyand essential performance of surgical luminaires and luminaires for diagnosis

IEC 60601-2-43 ed2.0Medical electrical equipment - Part 2-43: Particular requirements for the basic safetyand essential performance of X-ray equipment for interventional procedures

IEC 60601-2-44 ed3.1Medical electrical equipment - Part 2-44: Particular requirements for the basic safetyand essential performance of X-ray equipment for computed tomography

IEC 60601-2-45 ed3.0Medical electrical equipment - Part 2-45: Particular requirements for basic safety andessential performance of mammographic X-ray equipment and mammographicstereotactic devices

IEC 60601-2-46 ed2.0Medical electrical equipment - Part 2-46: Particular requirements for basic safety andessential performance of operating tables

IEC 60601-2-47 ed2.0Medical electrical equipment - Part 2-47: Particular requirements for the basic safetyand essential performance of ambulatory electrocardiographic systems

IEC 60601-2-49 ed2.0Medical electrical equipment - Part 2-49: Particular requirements for the basic safetyand essential performance of multifunction patient monitoring equipment

IEC 60601-2-50 ed2.0Medical electrical equipment - Part 2-50: Particular requirements for the basic safetyand essential performance of infant phototherapy equipment

IEC 60601-2-52 ed1.0Medical electrical equipment - Part 2-52: Particular requirements for the basic safetyand essential performance of medical beds

IEC 60601-2-54 ed1.0Medical electrical equipment - Part 2-54: Particular requirements for the basic safetyand essential performance of X-ray equipment for radiography and radioscopy

IEC 60601-2-57 ed1.0Medical electrical equipment - Part 2-57: Particular requirements for the basic safetyand essential performance of non-laser light source equipment intended fortherapeutic, diagnostic, monitoring and cosmetic/aesthetic use

IEC 60601-2-62 ed1.0Medical electrical equipment - Part 2-62: Particular requirements for the basic safetyand essential performance of high intensity therapeutic ultrasound (HITU) equipment

IEC 60601-2-63 ed1.0Medical electrical equipment - Part 2-63: Particular requirements for the basic safetyand essential performance of dental extra-oral X-ray equipment

IEC 60601-2-64 ed1.0Medical electrical equipment - Part 2-64: Particular requirements for the basic safetyand essential performance of light ion beam medical electrical equipment

IEC 60601-2-65 ed1.0Medical electrical equipment - Part 2-65: Particular requirements for the basic safetyand essential performance of dental intra-oral X-ray equipment

IEC 60601-2-66 ed1.0Medical electrical equipment - Part 2-66: Particular requirements for the basic safetyand essential performance of hearing instruments and hearing instrument systems

IEC 60601-2-68 ed1.0

Electrical medical equipment - Part 2-68: Particular requirements for the basic safetyand essential performance of X-ray-based image-guided radiotherapy equipment foruse with electron accelerators, light ion beam therapy equipment and radionuclidebeam therapy equipment

Appendix DPatient Environment

1

1.5 m 1.5 m

2.5 m

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Appendix E Example documentation template

i Effects of Electrical Current on Heart Rhythm, HOCHBERG, HOWARD M.1971

ii “Harm” is a defined term in ISO 14971:2000 as “physical injury or damage to the health of peopleor animals, or damage to property or the Environment”

iii In IEC 60601, safe levels of current are defined as 10µA AC / DC for CF applied parts and 100µAAC / 10µ DC for B / BF applied parts and touch current. Earth leakage limits are higher at 500µARMS for equipment with conductive accessible parts that may become live under a fault conditionand 5000µA RMS for earthed devices with no conductive accessible parts. Under fault conditions,higher values are allowed.

iv A free application note on this subject is available at; www.rigelmedical.com/rigel-downloads

v Comparing the tests of a 12 lead ECG (CF) monitor which requires 290 AC and DC leakagereadings under IEC 60601 (excluding SIP-SOP) and only 4 leakage readings in IEC 62353

vi Information gathered by Rigel Medical during over 40 international seminars on IEC 62353

Appendix E Example documentation template

Testing organisation: Test before putting into service (reference value)Recurrent Test

Test after repairName of testing person:

Responsible organisation:

Equipment:

Type: Production No./Serial Nr.:

Manufacturer: Class of protection: I II Battery

Applied part type: 0 B BF CF

Accessories:

Visual inspection:

Functional Test (parameters tested):

Deficiency / Note:

Overall Assessment:

Name:

PIE Permanent installed equipmentNPS Non-DETACHABLE POWER SUPPLY CORDDPS DETACHABLE POWER SUPPLY CORD

Date/Signature:

Next recurrent test necessary in 6 / 12 / 24 / 36 months

No safety or functional deficiencies were detected

No direct risk, deficiencies detected may be corrected on short term

Equipment shall be taken out of operation until deficiencies are corrected

Equipment does not comply – Modifications / Exchange of components / Taking out of service – is recommended

Measurements: Measured value

Protective earth resistance Ω

Equipment leakage current (according to Figure.....) mA

Patient leakage current (according to Figure....) mA

Insulation resistence (according to Figure.....) MΩ

Test:Measurement equipment:

Complies

Yes No

Mains connection: PIE NPS DPS

ID Number:

1)

1)

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Electrical Safety Analysers

The Rigel range of battery powered electrical safety testersoffers an accurate and fast solution for meetinginternational and local safety standards.

These uniquely designed testers incorporate anuncompromised list of test features within one compactunit, including automatic leakage, earth bond andinsulation testing to international and local standardsincluding IEC 62353, 60601-1 and NFPA-99.

An integrated keyboard enables detailed equipment datato be stored on-board alongside electrical safety testresults; providing complete traceability of results.

With a choice from 2 up to 10 individual patient leakagecircuits, we have the right solution to test any medical

equipment, from beds to multi-parameter monitors in a single test routine.

A combined high and low earth bond test current ensuresaccurate resistance measurements are made and thatpoor mechanical connections can be identified.

Automatic warnings of incorrect test setups help to avoidfalse readings, for example when secondary earth pathsare present, providing confidence in results and enablingimproved patient safety.

Use the Rigel safety analysers with Med-eBase softwareto unlock enhanced customisation features, createbespoke test templates and improve traceability andmanagement of test results.

Rigel 288+ and 62353+Electrical Safety Analysers

Scan QRcode to findout more

Functions available under battery power

Tests Earth bond • Insulation

Data transfer Download results Upload sequences, templates and assets

Scanning Barcode

Printing Results • Pass/Fail labels

Setting upTest sequences • Test codes • Asset trace variables – site, location etc • Bluetooth System configuration • Viewing results/data

t Features 288+ 62353+

IEC 60601* leakageIEC 62353 leakageIEC 61010 leakageApplied PartsMax earthbond currentPoint to point measurement Insulation testIEC lead test Manual modeAutomatic modeCustom test sequencingBattery operation Data storage Data entryBarcode scanning PC downloadSecondary earth warningLine voltage checkDirect print facilityWeight (kg)

n

n

n

1030A**

n

n

n

n

n

n

n

n

ABCDn

n

n

n

n

<1.7

n

230A**

n

n

n

n

n

n

n

n

ABCD

n

n

n

<1.7

* including all local derivitives (AAMI, NFPA, AS/NZ, VDE)** using high current low energy method

Product Benefits:

Full complianceHave peace of mind when it comes to having to comply with(international) standards andrecommendations including IEC 62353 and leakage tests inaccordance with IEC 60601, NFPA, AAMI and AS/NZ 3551.

Battery poweredSave valuable time by usingstandard AA batteries to keep yourtester operational in between testswhen moving from one mainssocket to the next.

Automated testingSave time and money by automatingtest procedures, and be assured thattest procedures are performed in aconsistent manner.

Electronic data storageReduce the risk of data captureerrors or manipulation and speed-upadministration with automated data storage.

Automatic test verificationGet the correct results first time andavoid time-consuming re-tests withRigel’s unique and automatedverification of secondary earth pathsand incoming mains configurations.

Unique earth bond technologyRigel’s unique high current, lowenergy earth bond test, givesaccurate and precise readings,saving time and unnecessaryreplacement of good mains cables.

Smallest and most compactReduce the burden of carryingmultiple instruments from site to siteby using the most compact electricalsafety analyser on the market.

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Version 1.0_2015

Rigel Medical, Bracken Hill, South West Industrial Estate,Peterlee, County Durham, SR8 2SW United Kingdom

Tel: +44 (0) 191 587 8730 Fax: +44 (0) 191 586 0227Email: [email protected] Web: rigelmedical.com

Part of