earthing fault

Electrical Earthling Construction, Faults & Protection Given the importance of electric power as one of the basic elements of economic and social development has provided a lot of countries support the electricity sector, by producing power electricity projects resulting in a significant expansion in using devices & equipments run on electricity.

2011

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1/1/2011

ELECTRICAL EARTHLING

Hossam Ahmed Zein

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Introduction Given the importance of electric power as one of the basic elements of economic and social development has provided a lot of countries support the electricity sector, by producing power electricity projects resulting in a significant expansion in using devices & equipments run on electricity.

In other way exist the electrical dangerous like fires, electric shocks and other so we must use … (Earth Leakage Circuit Breakers) for electrical leakage protection. (Will be mentioned in details…)

Likely to feel the normal person that often do not impact the ground on the electrical systems or devices through its normal operating, Which give the false impression that it is possible to separate the ground without notice any effects as a result it appears (seemingly only) that the b ground good contact with the ground poor is not a do not know the importance of the effectiveness of the ground unless it conducted periodic surveys from time to time.

The grounding is required to provide for the safety of the electrical system and the staff a

t the facility and this is known in general among some of people, but is not clear the most of them how to achieve that.

Benefits:

Firstly: personal protection of electric shocks caused by Isolation failure.

Secondly: protection from Electrical Discharging.

Thirdly: Protect devices from sudden changes in Voltage source.

Fourthly: Reduce the likelihood of damage as a result of lightning or fault currents, Lightning Strikes,

Static Discharges, EMI and RFI signals and Interference.

Fifthly: Functional earthling in electrical power system.

The agencies and organizations all have recommendations and / or standards for grounding, to ensure that personnel safety is being protected. The organizations that provide guide lines/rules for grounding are: The International Electrotechnical Commission (IEC), European Committee for Electrotechnical Standardization (CENELEC), Underwriters Laboratories (UL), National Fire Protection Association (NFPA), American National Standards Institute (ANSI), Mine Safety Health Administration (MSHA), Occupational Safety Health Administration (OSHA), Telecommunications Industry Standard (TIA) and others.

Instrument And Devices Must be Earthed:

To make Good ground Network, it is necessary to ground the following elements: - All metal objects vertically and more than 240 cm in length or extended horizontally and more than 150 cm in length and are exposed to contact. - All electrical appliances. - All Albriz exits رج ا��ا�� and lighting units.


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General Concepts Step Voltage :

The difference in surface Potential experienced by a person bridging a distance of 1 meter with his feet without contacting any grounded object.

Touch Voltage ;

Potential difference between rise and surface potential at the point where the person standing while in the same time having his hand contact with grounded structure.

Mesh Voltage :

The max. touch voltage within a mesh of groun grid.

Transferred Voltage :

A special case of touch voltage where a voltage is transferred into or out a substation from or to a remote point external to the substation site.


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Standards Ideal Ground Resistance should be Zero ohm But practically, it must be lower than 25 ohm for power systems & 5 ohm For Telecommunication System achieved by increasing no. of ground electrodes.

v It is at least 2,4 m in length and in contact with the soil. There are 3 variables that affect the resistance of a ground electrode: a) The ground material Itself. b) The length/depth of the ground electrode.

• Very effective way of lowering resistance is to drive ground electrodes deeper. Because the earth is in layers resistivity changes and varies considerably on the layer and the depth within that layer.

c) Diameter of the ground electrode. • Increasing the diameter of the ground electrode has very little effect in lowering the

resistance. For example you could double the diameter of a ground electrode and your resistance would only decrease by as much as 10 %.

d) Chemical Treatment OF the soil: • Making a hole Beside the grounding electrode with max. distance 10 cm and filled of salts

Mg3SO4 ت ال�� ي Or آ�� ا��س Or Cu2SO4�� آ�� till 30 cm from surface level . • By making circular tenth around the electrode with (45 cm-Diameter) & (30 cm-Depth) and

filled with pre-mentioned chemicals ,with no direct contact to the electrode other else corrosion Occur. § The chemicals recommended to be Cu2SO4 with around (18-40 Kg) as it’s cheap , Good

electrical conductivity and the long run effect (2 years) • Flood the grounding hole with water for good absorption of salts (chemicals) periodically

that what rain water do.

Largest copper conductor Diameter )mm2(

diameter to the Ground conductorcopper Electrode )mm2(

1 1 1.5 1.5 2.5 2.5 4 4 6 6

10 10 16 16 25 16 35 16 50 25 70 35 95 50 120 70 150 70 185 95 240 120 300 150 400 185

The allowed Current passing through the Grounding conductor


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Conductor Diameter

(2 mm)

Allowed Current for long time (A)

Instantaneous Current

(A/sec.)

Cu AL Cu Al

16 150 - 2500 -

25 200 160 4000 2700

35 280 200 5500 3700

50 480 250 8000 5300

70 590 320 11500 7400

95 780 430 11600 10500

185 1380 760 32500 21000

Relation between Leakage Current Intensity & Its passing through time in human body

Current (mA) passing through time Biological effect on Human

body

0 – 0.5 �س و�� ا��!ر ��

0.5 – 5 �� %-,أ ا�*�( &!)'�!س &!��!ر و%�$#

�7/�!ن ا��345 �# ا��2,ر إ0 أ/� %��ك ا��>��;�!رًا 89 �$!ن

5 – 30 B,ة د?!<= GH2% ا2F/0!ل B# �2,ر ا�$�D&!ء �FI� =�Jا�,م و LMJ ع!Fار� G-�%و

30 – 50 �ا/8 � OP& G4Qا� R-/ م!S�/م ا,B– ا�,م LMJ OF��%

�O إ��!ء

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VP-Iل �# �,ة ا��Yأ LQ/ ,IB ر ;�!ر�DZ O� !ء��ا��>��إ

أآ]� �# B,ة �U!تVP-Iة ا�,� #� W?ا��>�� أ LQ/ ,IB ر ;�!ر�DZ O� !ء��إ

VP-Iل �# �,ة ا��Y!ء أ��ت أو '�%= –إ��


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E) Number of ground electrodes • In this design, more than one electrode is driven into the

ground and connected in parallel to lower the resistance. For additional electrodes to be effective, the spacing of additional rods needs to be at least equal to the depth of the driven rod.

F) Ground system design • Mentioned After ….


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Ground electrode: You can use one of the following means of grounding pole, namely:

1 - Extensions of metal pipes for water.

2 - Reinforcing rods ��أ*�خ ا�� of the building.

3 - A metal conductor is extended around the building and not less than 75 cm from the surface of the earth.

4-Specialised Industrial Electrodes:

i. Made Electrode: It is a metal rod or pipe not less than 240 cm in length buried vertically in contact with the soil unless the ground is rocky and can be placed diagonally 45 degrees to the vertical level, or buried in a trench ق-�. at a depth of 75 cm from the surface of the earth at least.

ii. Plate Electrode: It is a sheet metal may be copper (1.5 mm-thick) OR Iron (6.35mm-min. thickness) , with min. expose area 186 m2

a. Free Of grease or Oils because they undermine the viability of the properties of the grounding of the conductivity.

The Electrode consists of three basic components:

1. Ground conductor 2. The connection/bonding of the conductor to the ground electrode 3. The ground electrode itself.

The resistance of a ground electrode has 3 basic components:

A) The resistance of the ground electrode itself and the connections to the electrode. • it's connection is generally very low, ground rods are generally made of highly

conductive/low resistance material such as copper of copper clad.

B) The contact resistance of the surrounding earth to the electrode.

• The Bureau of Standards has shown this resistance to be almost negligible providing that the ground electrode is free from paint, grease etc. and that the ground electrode is in firm contact with the earth

B) The resistance of the surrounding body of earth around the ground electrode. The resistance of a ground

• The ground electrode is surrounded by earth which is made up of concentric shells all having the same thickness. Those shells closest to the ground electrode have the smallest amount of area


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resulting in the greatest degree of resistance. Each subsequent shell incorporates a greater area resulting in lower resistance. This finally reaches a point where the additional shells offer little resistance to the ground surrounding the ground electrode.

Types Of grounding According to the Protective Device

Earth grounding

is an intentional connection from a circuit conductor usually the neutral to a ground electrode placed in the earth.

Equipment grounding

is to ensure that operating equipment within a structure is properly grounded.

These two grounding systems are required to prevent differences in potential from a possible flashover from a lightning strike.

According to the Design Simplicity

• Simple grounding systems consist of single ground electrode driven into the ground. The use of a single ground electrode is the most common form of grounding. • Where: outside your home or place of

business.

1. Complex grounding systems consist of multiple ground rods, connected, mesh or grid networks, ground plates, and ground loops. o Where: at power generating substations,

central offices, and cell tower sites.

According to its Design techniques

a. Single ground electrode. b. Multiple ground electrodes connected. c. Mesh network. d. Ground plate.

Complex networks increase the amount of contact with the surrounding earth and lower ground resistances.


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According to its fuctionality :-

1. Functional grounding: this kind of grounding is related to the proper work of the system like (neutral point grounding, reactors grounding ..etc.)

2. Protective grounding: This kind related to personal protection due electric shocks and its about connecting all conducting of non-current carrier with earth

3. Lighting Protection: Protect the system from lighting discharging any traveling waves or equip the substation with equipments to discharge the lighting as it happen

Ground Fault Protection Circuit Breakers

Electrical circuits Protected by Normal cit. breakers (15-20) -- 60 mA Cause human Death – and it’s so sensitive for the lowest current .

Types Of Circuit breakers:

1st Type: it shutdown the cit. when the passing current about 6 mA .

2ndType: it shutdown the cit. when the passing current about 20 mA .

Where Cit. Breakers Connected (Elcb):

i. Elcb circuit breaker Connected on the main power line for General protection for all circuits, (Main Protection)

But it cause total current break down for any current leak in any following circuits (lighting)

ii. Using two cit. breakers , one (normal) for the main lighting board and the other (Elcb) for the main power board .


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iii. Could be used for distinct device ( air conditioner ) condition that this device must be earthed. Or

for apart of home or some place (Individual Protection)


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Hossam Ahmed Zein

Structural lightning protection Design considerations

Structural lightning protection design considerationsBS 6651 (Protection of structures against lightning) clearly advises strict adherence to the provision of a conventional Lightning Protection System (LPS) other device or system for which claims of enhanced protection are made. The principle components of a conventional structural lightning protection system, in accordance with BS 6651 are:

Air Termination Network

Down Conductors

Structural lightning protection esign considerations

Structural lightning protection design considerations BS 6651 (Protection of structures against lightning) clearly advises strict adherence to the

Lightning Protection System (LPS) - to the total exclusion of any other device or system for which claims of enhanced protection are made.

The principle components of a conventional structural lightning protection system, in accordance with BS 6651 are:

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Structural lightning protection &

BS 6651 (Protection of structures against lightning) clearly advises strict adherence to the to the total exclusion of any

other device or system for which claims of enhanced protection are made.

The principle components of a conventional structural lightning protection system, in

http://www.furse.com/elp/lpov.htm#Air

http://www.furse.com/elp/lpov.htm#Down


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Earth Termination Network

Bonding (to prevent side flashing)

Other areas that need to be looked at:

Corrosion

Inspection, testing, records and maintenance

Air termination network On high risk structures such as explosive factories, no part of the roof should be more than 2.5m from an air termination conductor. This is generally achieved by applying a 5m x 10m mesh to the roof. However, for most structures, a mesh of 10m x 20m is considered sufficient, giving a maximum distance from any part of the roof to the nearest conductor of 5m.

Air terminations for tall conducting structures The zone of protection does not seem to be applied because of the need to interconnect the down conductors of the tall block to the air termination of the lower block. In such cases it is necessary to connect tup to the lower down conductors to facilitate this inter connection, even though this extension is within the zone of protection of the tower.

The 'Zone of Protection' offered by an air termination network is considered to beheights up to 20m. Above this height, the zone of protection is determined by the 'Rolling Sphere Method'.

This involves rolling an imaginary sphere of 60m radius over a structure. The areas touched by the sphere are deemed to require protection. the sides of the building. Zones of protection

Bonding (to prevent side flashing)

Other areas that need to be looked at:

Inspection, testing, records and maintenance

On high risk structures such as explosive factories, no part of the roof should be more than n conductor. This is generally achieved by applying a 5m x 10m

However, for most structures, a mesh of 10m x 20m is considered sufficient, giving a maximum distance from any part of the roof to the nearest conductor of 5m.

The zone of protection does not seem to be applied because of the need to interconnect the down conductors of the tall block to the

In such cases it is necessary to connect the lower air termination up to the lower down conductors to facilitate this inter connection, even though this extension is within the zone of protection of the

The 'Zone of Protection' offered by an air termination network is considered to beheights up to 20m. Above this height, the zone of protection is determined by the 'Rolling

This involves rolling an imaginary sphere of 60m radius over a structure. The areas touched by the sphere are deemed to require protection. On tall structures, this can obviously include

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On high risk structures such as explosive factories, no part of the roof should be more than n conductor. This is generally achieved by applying a 5m x 10m

However, for most structures, a mesh of 10m x 20m is considered sufficient, giving a maximum distance from any part of the roof to the nearest conductor of 5m.

The 'Zone of Protection' offered by an air termination network is considered to be 45º for heights up to 20m. Above this height, the zone of protection is determined by the 'Rolling

This involves rolling an imaginary sphere of 60m radius over a structure. The areas touched On tall structures, this can obviously include

http://www.furse.com/elp/lpov.htm#Earth

http://www.furse.com/elp/lpov.htm#Bonding

http://www.furse.com/elp/lpov.htm#Corrosion

http://www.furse.com/elp/lpov.htm#Inspection


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Down conductors Down conductor siting and distancing is often dictated by architectural circumstances. There should be one down conductor for every 20mor ground level (whichever is greater). These should be evenly spaced and distances apart of more than 20m avoided if possible. If the building is above 20m in height or of an abnormal risk this distance to 10m. They should be routed as directly as possible from the air termination network to the earth termination network to avoid risks of side flashing. ReBS 6651 recommends that the length of condutimes the width of its open side. BS 6651 allows the use of 'natural conductors' such as rebars and structural steelwork, provided that they are electrically continuous and adequately earthed. Lightning Protection Scheme to BS 6651 using the reinforced concrete within the structure for down conductors

Earth termination networkEach down conductor must have a separate earth termination. Moreover provision should be made in each down conductor, for disconnection from the earth for testing purposes. This is achieved with a test clamp (see below). BS 6651 stipulates the resistance to earth lightning protection measured at any should not exceed 10 the test clamp disconnected, the resistance of each individual earth should

Down conductor siting and distancing is often dictated by architectural circumstances. There should be one down conductor for every 20m or part thereof of the building perimeter at roof or ground level (whichever is greater). These should be evenly spaced and distances apart of more than 20m avoided if possible.

If the building is above 20m in height or of an abnormal risk this distance

They should be routed as directly as possible from the air termination network to the earth termination network to avoid risks of side flashing. Re-entrant loops are also to be avoided. BS 6651 recommends that the length of conductor forming the loop should not exceed eight times the width of its open side.

BS 6651 allows the use of 'natural conductors' such as rebars and structural steelwork, provided that they are electrically continuous and adequately earthed.

ction Scheme to BS 6651 using the reinforced concrete within the structure for down conductors

Inner area requires no conductors as it is within the zone of protection determined by the rolling sphere

Earth termination network conductor must have a separate earth termination. Moreover provision should be

made in each down conductor, for disconnection from the earth for testing purposes. This is achieved with a test clamp (see below).

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Down conductor siting and distancing is often dictated by architectural circumstances. There or part thereof of the building perimeter at roof

or ground level (whichever is greater). These should be evenly spaced and distances apart of

If the building is above 20m in height or of an abnormal risk this distance should be reduced

They should be routed as directly as possible from the air termination network to the earth entrant loops are also to be avoided.

ctor forming the loop should not exceed eight

BS 6651 allows the use of 'natural conductors' such as rebars and structural steelwork,

ction Scheme to BS 6651 using the reinforced concrete within the

Inner area requires no conductors as it is within the zone of protection

conductor must have a separate earth termination. Moreover provision should be made in each down conductor, for disconnection from the earth for testing purposes. This is

that of the system point, ohms. With

be no


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more than ten times the number of down conductors in the complete system. eg fosystem with 15 down conductors, the individual earth readings should be no more than 10 x 15 = 150 ohms. Several types of earth electrode are permissible, but by far the most commonly used are deep driven earth rods. BS 6651 states that the combined eshould be no less than 9m whilst each individual earth rod should be no less than 1.5m in length.

Deep drivenearth electrode

Parallel earth rod electrodesWhere ground conditions make of rods coupled to one another by conductors can be used. If possible, the earth rods must be spaced at a distance at least equal to their driven depth. If earth rods cannot be driven in a parallensuring that the spacing/depth ratio is still maintained. High resistivity soil conditions can be overcome by backfilling earth rods with a suitable medium such as Marconite conductive concrete which effethe earth rod and hence its surface area, thus lowering resistance to earth.

more than ten times the number of down conductors in the complete system. eg fosystem with 15 down conductors, the individual earth readings should be no more than 10 x

Several types of earth electrode are permissible, but by far the most commonly used are deep driven earth rods. BS 6651 states that the combined earth rod length of a system should be no less than 9m whilst each individual earth rod should be no less than 1.5m in

Deep driven earth electrode

Oblong test orjunction clamp

Parallel earth rod electrodes Where ground conditions make deep driving of earth rods impossible, a matrix arrangement of rods coupled to one another by conductors can be used. If possible, the earth rods must be spaced at a distance at least equal to their driven depth.

If earth rods cannot be driven in a parallel line a "Crows Foot" configuration can be used, ensuring that the spacing/depth ratio is still maintained.

High resistivity soil conditions can be overcome by backfilling earth rods with a suitable medium such as Marconite conductive concrete which effectively increases the diameter of the earth rod and hence its surface area, thus lowering resistance to earth.

Spacing of parallel earth rod electrode

Pa

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more than ten times the number of down conductors in the complete system. eg for a system with 15 down conductors, the individual earth readings should be no more than 10 x

Several types of earth electrode are permissible, but by far the most commonly used are arth rod length of a system

should be no less than 9m whilst each individual earth rod should be no less than 1.5m in

Oblong test or junction clamp

deep driving of earth rods impossible, a matrix arrangement of rods coupled to one another by conductors can be used. If possible, the earth rods must

el line a "Crows Foot" configuration can be used,

High resistivity soil conditions can be overcome by backfilling earth rods with a suitable ctively increases the diameter of

the earth rod and hence its surface area, thus lowering resistance to earth.

earth rod electrode


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Bonding All metal work, including water pipes, gas pipes, handrails, air conditioning cladding, metal roofs etc, in the vicinity of the LPS must be bonded to it, to avoid the danger of side flashing. For the same reason, the LPS earth should be bonded to the main electrical earth, as well as any other earthing system present i

All metal work, including water pipes, gas pipes, handrails, air conditioning cladding, metal roofs etc, in the vicinity of the LPS must be bonded to it, to avoid the danger

For the same reason, the LPS earth should be bonded to the main electrical earth, as well as any other earthing system present in the structure.

Example of side flashing If the lightning protection system on a structure is hit by lightning, then the current flowing through the system and the resistance/impedance offered by the conductor path will determine themagnitude of the potential difference seen by the lightning conductors with respect to true earth. The lightning conductors can, instantaneously, have a potential magnitude of megavolts (1,000,000V) with respect to true earth. Typically, at instant of discharge: Potential difference at A = 1,500,000V Potential difference at B = 0V

Bonding to prevent side flashing

1 Air termination

2 Down conductor

3 Bond to aerial

4 Bond to vent

5 Bond to re-

6 Bond to metal staircase

7 Bond to metal window frame

8 Bond to vent pipe

9 Bond to steel door/frame

10 Test clamp

11 Indicating plate

12 Main earthing terminal of electrical installation

13 Earth termination point Pa

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All metal work, including water pipes, gas pipes, handrails, air conditioning units, metal cladding, metal roofs etc, in the vicinity of the LPS must be bonded to it, to avoid the danger

For the same reason, the LPS earth should be bonded to the main electrical earth, as well as

If the lightning protection system on a structure is hit by lightning, then the current flowing through the system and the resistance/impedance offered by the

otential difference seen by the

The lightning conductors can, instantaneously, have a potential magnitude of

Bonding to prevent side

Air termination

Down conductor

Bond to aerial

Bond to vent

-bar

Bond to metal staircase

Bond to metal window frame

to vent pipe

Bond to steel door/frame

Test clamp

Indicating plate

Main earthing terminal of electrical installation

Earth termination point


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Corrosion BS 6651 contains tables of materials suitable for use in lightning protection system components. Adherence to these requirements is vital to avoid corrosion problems. The correct choice of material and installation design should ensure a life span of 30 years for the earth electrode system.

Measurement There are three methods of Earth ground testing methods :

1) Soil Resistivity (using stakes)

Why: Soil Resistivity is most necessary when deter-mining the design of the grounding system for new installations (green field applications) to meet your ground resistance requirements.


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Lowest Resistance is petter ,if it was high enough could be overcomed with more elaborate ground systems

Requirements: replacing the electrode as deeper as possible

• where, soil and water exist (/01 3�1 أو) water table.

• where there is a stable temperature, i.e. below the frost line.

Depend on:

Soil Content of Moisture : The Soil Resistivity decreases significantly due increasing of its content of moisture


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Temperature: If temp. of Soil was too high the Soil Resistivity increase & if temp. was too low (subzero) then the moisture will freeze and the Resistivity will increase .

Electric Current : If the current was too high then it will produce a heat all over the carrying conductors ,this heat will dry the moisture and increase the resistivity .

Depth of Soil : that the content of moisture increases as we get deeper within the ground unless re a rock base.

2) Fall-of-Potential (using stakes) : The Fall-of-Potential test method is used to measure the ability of an

earth ground system or an individual electrode to dissipate energy from a site. Procedure: >Disconnect the earth electrode

i. Two stakes (inner & outer) are placed in the soil in a direct line, away from the earth electrode with indicated table

ii. Connect earth tester to the electrode

iii. Using Ohm’s Law (V = IR), a known current is generated by the test device between the outer stake (auxiliary earth stake) and the earth electrode, while the drop in voltage potential is measured between the inner earth stake and the earth electrode.

3) Selective (using 1 clamp and Auxiliary stakes)

Ø The earth electrode of interest does not need to be disconnected from its connection to the site.

Ø Much safer and easier way

Procedure: >

i. a special clamp is placed around the earth electrode, which eliminates the effects of parallel resistances in a grounded system

ii. is very similar to the Fall-of-Potential testing, providing all the same measurements.

4) Stake-less [UNILAP GEO X](using 2 clamps only)

Ø Comparative advantage: o measure earth ground loop resistances for parallel / multi-

grounded systems using only current clamps. o Used inside buildings, on power pylons or anywhere you

don’t have access to soil. Ø Produce operating safety and Less Dangerous.


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Ø If there is only one path to ground, the Stakeless method will not provide an acceptable value and the Fall-of-Potential test method must be used.

Procedure :>

i. Two clamps are placed around the earth ground rod or the connecting cable and each are connected to the tester.

ii. A known voltage is induced by one clamp, and the current is measured using the second clamp. iii. The tester automatically determines the ground loop resistance at this ground rod.

Some Practical Examples:


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Cellular sites/microwave and radio towers

At most locations there is a -legged tower with each leg individually grounded. These grounds are then connected with a copper cable. Next to the tower is the Cell site building, housing all the transmission equipment. Inside the building there is a halo ground and a MGB, with the halo ground connected to the MGB. The cell site building is grounded at all corners connected to the MGB via a copper cable and the corners are also interconnected via copper wire. There is also a connection between the building ground ring and the tower ground ring.

Electrical Substations

A substation is a subsidiary station on a transmission and distribution system where voltage is normally transformed from a high value to low value. A typical substation will contain line termination structures, high-voltage switchgear, one or more power transformers, low-voltage switchgear, surge protection, controls, and metering.


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Lightning protection at commercial/industrial sites

Most lightning fault current protection systems follow the design of having all four corners of the building grounded and these are usually connected via a copper cable. Depending on the size of the building and the resistance value that it was designed to achieve, the number of ground rods will vary.

Ø Stakeless measurement

First, perform a Stakeless measurement on:

• The individual legs of the tower and the four corners of the building (cell sites/towers)

• All grounding connections (electrical substations)

• The lines running to the remote site (remote switching)

• The ground stakes of the building (lightning protection)

Ø 3-pole Fall-of-Potential measurement

This measurement should be recorded and measurements should take place at least twice per year.

This measurement is the resistance value for the entire site.

Ø Selective measurement

The resistances should be measured on:

• Each leg of the tower and all four corners of the building (cell sites/towers)

• Individual ground rods and their connections (electrical substations)

• Both ends of the remote site (remote switching)

• All four corners of the building (lightning protection)

Measuring of High Voltage Trans. Towers 1


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Remote switching sites (known as slick sites)

Where digital line concentrators and other telecommunications equipment is operating.

The remote site is typically grounded at either end of the cabinet and then will have a series of ground stakes around the cabinet connected by copper wire.

Stackless method

Fall of potential 1 Fall of potential 2

earthing fault

Education

ground material

ground poor

electrical power system

electrical systems

b ground good contact

good ground network

electrical discharging

electrical appliances