Electrical hazards are present in all laboratories. Adherence to all electrical safety standards is essential in preventing electrical

accidents

A COMPLETE CIRCUIT OR LOOP IS NECESSARY FOR CURRENT TO FLOW

ELECTRICITY IN THE BODY

Muscles

Muscles control all the body movements

Including & importantly those that keep us alive - Breathing and Heart

The brain controls voluntary muscles using Current pulses along nerves

ELECTRICITY IN THE BODY

External current through the body causes

Loss of muscle control

Spasms & Involuntary movement

Inability to let go

Burns - external & internal

The severity and effects of an electrical shock depend on a number of factors,

such as

The pathway through the body The amount of current The length of time of the exposure Whether the skin is wet or dry.

PHYSIOLOGICAL EFFECTS OF ELECTRICITY

Current Reaction

1-5 MilliampereSlight shock felt; not painful but

disturbing

6-30 Milliamperes Painful shock; "let-go" range

50-150 Milliampere

Extreme pain, respiratory arrest, severe muscular contraction

1,000-4,300 Milliamperes

Ventricular fibrillation

10,000+ Milliamperes

Cardiac arrest, severe burns, and probable death

ELECTRICAL HAZARDS Major hazards associated with electricity are electrical shock and fire.

Electrical shock occurs when the body becomes part of the electric circuit , when:

• An individual comes in contact with both wires of an electrical circuit.

• One wire of an energized circuit and the ground.• Or a metallic part that has become energized by contact with an

electrical conductor.

In addition to the electrical shock hazards, sparks from electrical equipment can serve as an ignition source for flammable or explosive vapors.

Loss of electrical power can result in extremely hazardous situations:

Flammable or toxic vapors may be released as a chemical warms when a refrigerator or freezer fails.

Fume hoods may cease to operate, allowing vapors to be released into the laboratory.

COMMON ELECTRICAL PROBLEMS

Extension Cords and Power Strips Power Cords Solvents and Electricity Water and Electricity Laboratory Equipment Capacitors and Transformers

POWER STRIPS ARE APPROVED FOR USE ONLY WITH COMPUTERS AND COMPUTERIZED EQUIPMENT. POWER STRIPS SHOULD BE USED SPARINGLY. CARE MUST BE TAKEN NOT TO OVERLOAD POWER STRIPS.

EXTENSION CORDS ARE APPROVED FOR TEMPORARY USE ONLY. IF EXTENDED USE IS REQUIRED, HARD WIRING SUCH AS A NEW OUTLET SHOULD BE INSTALLED. EXTENSION CORDS ARE EASILY FRAYED, A CONDITION WHICH MAY EXPOSE BARE WIRES.

Power cords are doubly insulated and should be replaced if the outer layer of insulation becomes frayed exposing wires.

POWER CORDS

Avoid dangling cords and cords at floor.

OVERLOADS OCCUR WHEN MORE CURRENT FLOWS THROUGH A CORD THAN IT IS RATED TO HANDLE. POWER STRIPS CAN BE OVERLOADED IF TOO MANY HIGH CURRENT DRAW DEVICES ARE PLUGGED IN AT ONE TIME

COMMON LABORATORY EQUIPMENT SUCH AS CENTRIFUGES AND OVENS ARE HIGH CURRENT DRAW DEVICES. IF TWO OR MORE HIGH CURRENT DRAW DEVICES ARE PLUGGED INTO THE SAME OUTLET OR POWER STRIP AN OVERLOADED CIRCUIT MAY RESULT.

CARE MUST BE TAKEN TO INSURE THAT POWER CORDS DO NOT COME IN CONTACT WITH HOT SURFACES SUCH AS THE TOP OF A HOT PLATE WHERE THEY MAY MELT

EXPOSING BARE WIRES .

POWER STRIPS MUST BE LOCATED OUTSIDE OF ANY FUME HOOD WHERE FLAMMABLE VAPORS ARE PRESENT.

WATER AND ELECTRICITY

Eyewashes should be located away from electrical devices and outlets. Outlets within six feet of a sink or other source of plumbing must be protected in order to minimize shock hazards. An unprotected outlet is illustrated in this picture

Safety showers must not be located directly over switches, outlets, equipment, or other sources of electrical energy such as those shown in the picture to the left.

POWER SUPPLIES REPRESENT A POTENTIALLY LETHAL SOURCE OF ELECTRICAL ENERGY. EXPOSED CONNECTORS SUCH AS BANANA CLIPS (ALLIGATOR CLIPS) SHOULD NEVER BE ATTACHED TO A POWER SUPPLY OR ANY OTHER HIGH VOLTAGE, HIGH CURRENT PRODUCING DEVICE.

Electrophoresis equipment containing high voltage power supplies are found in many laboratories.

Care must be taken to use only approved equipment.

Leads should be checked periodically for frays.

Flammable storage refrigerators are specially designed for flammable liquid storage. The interior of these types of refrigerators do not contain any potential spark sources such as lights and switches.

BASIC ELECTRICAL SAFETY GUIDELINES Learn the location of your electrical panels and shut-off

switches so you can quickly disconnect power in the event of an emergency. Always leave at least a 3-foot clearance around electrical panels for ready access.

Plan ahead for what steps will be taken in the event of a power loss.

Conduct a periodic inspection of laboratory electrical

equipment to be sure it is in good condition.

Electrical outlets should have a grounding connection and accept three-prong plugs. Multiple plug outlet adapters are not allowed.

ELECTRICAL FIRES

• Unplug equipment first.• Use dry chemical fire

extinguisher.• If fire is large, unplug

equipment and call fire dept.

• Never use water!!.

Type A fire extinguishers use water to put out fires. They are not approved for use on electrical fires. Type A extinguishers are denoted by a pressure gauge at the top of the unit that indicates whether or not the extinguisher is fully charged