ELECTRICAL SAFETY

AWARNESS TRAINING

Training Program

Updated 5/5/04

Electrical Fires in the USA

Daily, fires occur due to electrical problems: defective

electrical device, circuit overloading, circuit overheating,

explosions ignited by electrical spark, etc.

Electricity is one of the most common causes of fire in the

USA. Each year there are approximately:

1.6 million fires (all causes) reported,

causing 3,600 fire deaths,

18,000 fire related injuries,

$10.7 billion in property damage.

Source: National Fire Protection Association, 2007

GroundingWhat is Grounding?

“Grounding” a tool or electrical system means intentionally creating a low-resistance path that connects to the earth. This prevents the buildup of voltages that could cause an electrical accident.

Grounding is normally a secondary protective measure to

protect against electric shock. It will substantially reduce the

risk of injury or death in case of shock, especially when used

in combination with other electrical safety measures.

An equipment ground helps protect the equipment operator.

It furnishes a second path for the current to pass through

from the tool or machine to the ground. This additional

ground safeguards the operator if a malfunction causes the

tool’s metal frame to become energized. The resulting flow

of current may activate the circuit protection devices.

ProtectionOvercurrent Protection

Fuses and circuit breakers open/break the circuit automatically when too much current flows through them.

This is designed to protect the wiring/equipment from overheating and possible damage – NOT THE USER

GFCI (Ground Fault Circuit Interrupter)

Used in wet and other high-risk areas.

Stops the flow of electricity when there is

a difference between current leaving and

returning from the outlet.

• Should be tested monthly

Push test button and then the reset button

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Power Extension Cords and Power

StripsExtension Cords & Power Strips are for TEMPORARY use only!

They may not be run through doorways, ceilings or windows

Power Strips (Transient Voltage Surge Suppressors)

FOR ELECTRONICS ONLY (Computer Equipment etc.)

NOT FOR APPLIANCES (Refrigerator, Microwave Toaster, Coffee Pot, Water Cooler etc.)

Do not overload

The number of outlets on the power

strip does not indicate how many

devices can be connected

Properly Used Power Strip

EXAMPLES OF A PROPERLY

USED POWER STRIP

STRIP IS NOT OVERLOADED

ONLY COMPUTER

(ELECTRICAL) EQUIPMENT

IS ATTACHED TO STRIP

CORDS ARE KEPT NEAT

NO EXTENSION CORDS ARE

ATTACHED TO POWER

STRIP

POWER STRIP IS ATTACHED

DIRECTLY TO WALL

OUTLET-NO EXTENSION

CORD IS USED

Improperly Used Power StripEXAMPLES OF AN IMPROPERLY

USED POWER STRIP

POWER STRIP IS OVERLOADED

DUE TO MINI-FRIDGE,

MICROWAVE, AND TWO-POT

COFFEE MAKER ALL ON ONE

POWER STRIP

APPLIANCES ARE CONNECTED

TO A POWER STRIP (THEY

SHOULD BE CONNECTED

DIRECTLY INTO A WALL OUTLET)

POWER STRIP IS NOT

CONNECTED DIRECTLY TO THE

WALL OUTLET - AN EXTENSION

CORD IS USED

EXTENSIONCORD IS USEDWITH POWER

STRIP

Damaged and Unapproved Devices

Cord plug with ground prong missing

Damaged TVSS rated power strip

Adapter enables circuit overload

Not Permitted:

Damaged and Unapproved Devices

Not Permitted:

Lamp extension cord, also damaged

Power taps

Adapter to change 3-prong plug

to 2-prong eliminating ground

7

Grounding Cable

Grounding Bus

or Electrode

Bonding Cable

• Proper grounding and bonding is used to address the dangers of static

electricity.

• In order for grounding to protect, all surfaces must be bonded together

and grounded to earth.

• Static electricity is thereby released to earth as it is generated,

preventing the accumulation of dangerous charges that may ignite

flammable / hazardous substances.

Container Bonding and Grounding

(Static Electricity)

Responsibilities

Entire system must be properly bonded and grounded to the earth

Facilities

Responsible for the system up to the wall outlet (all wiring and outlets)

User

Responsible for the condition of plug and cord of equipment

Inspect equipment to ensure plugs and cords are not damaged.

Do not break off third prong or use adaptors

No Prong = Not Grounded

Electrical Safety Incidents

The following is an example of :

Electrocution Due to Improper Use of

Common Equipment

Background

Dr. X was conducting an experiment related to plant growth. He needed to expose the plants to light for specific time-periods each day. Accordingly, he had a portable fluorescent lighting rack constructed and mounted on a wooden frame. He also obtained an electric timer to automatically turn the lights on and off. The light fixture was plugged into the timer, which was plugged into the wall outlet. However, since the timer only accepted a two prong plug, an adapter was used to allow the three prong plug of the lighting rack to be used with the two prong outlet of the timer.

The Incident

Dr. X adjusted the timer so that the lights would

be on and plugged the timer into a standard 3-

prong wall outlet. Then another person in the lab

noticed Dr. X grasping the lighting rack and

appearing to be rigid. A third person grasped Dr.

X by the shoulders and pulled him away from the

lighting rack. CPR was performed on him until

EMS arrived. Dr. X was transported to a hospital

where he was pronounced dead.

The Investigation

The investigation revealed the following details:

A potential difference of 397 volts was measured between the metal fluorescent light fixture and the adjacent stainless steel sink. (There should not have been any potential difference).

Both the fixture and the wall outlet were found to be wired correctly.

The light fixture was rated for 800 mA, but the lamps used were 1500 mA.

The transformer in the ballast was found to have short circuited to the case.

What Probably Happened

Use of bulbs drawing more current than approved for the fixture caused overheating of the ballast resulting in melting of insulation around the transformer coil. This allowed an energized transformer wire to touch the metal cover of the ballast which in turn energized the metal fluorescent fixture. The lights probably continued to function since they were wired correctly.

When Dr. X grasped the fixture, some part of him probably brushed against the nearby metal sink. This completed a circuit to ground through Dr. X, electrocuting him.

Preventing this Fatality

As with many very serious accidents, a number of factors were involved, any

one of which could have prevented this fatality.

If overrated lamps had not been used, the ballast would probably not have overheated and failed.

If the ground wire connection between the light fixture and the plug not been interrupted by the "cheater" adapter and the two-prong timer, the fixture would have safely shorted to ground tripping the circuit breaker when the equipment was plugged in before Dr. X touched it.

Had the standard outlet near the sink been Ground Fault Circuit Interrupter (GFCI) protected (as it should have been because it was near a sink), the GFCI would have tripped at the first flow of current through Dr. X immediately cutting off power to the fluorescent fixture and saving his life.

These electrical safety violations cost Dr. X his life. If any one of them had been

corrected before the incident, Dr. X would still be researching plant growth.

Don’t Let This Happen in Your Lab!1)Follow manufacturer's recommendations for use of electrical

equipment. Do not use electrical equipment for a task it is not designed

for.

2) Generally, equipment used in research should have a 3 prong plug or

be double insulated. Equipment with neither of these features are less

safe but may meet electrical codes. A 3 prong plug must always go into

a 3 prong outlet. Do not use a "cheater" plug or pull out the 3rd prong.

3) Do not use multiple cube taps in a standard outlet. If you must plug

more than two pieces of low demand equipment into a standard outlet,

use a fused power strip that will trip if too much power is used.

4) Make sure that any outlet near a sink or other water source is Ground

Fault Circuit Interrupter (GFCI) protected. If you have a GFCI,

periodically test it by plugging something into it and pushing the "test“

button. The equipment should turn off and then turn it back on.

…continued

5) If you see a person being electrocuted, DO NOT TOUCH HIM! The

electricity can go though you too. If possible, remove the power (pull

plug or trip circuit breaker), or use a non-conductive item (e.g. wooden

broom handle) to pry him away from the contact.

6) Above all, do not disable any electrical safety feature expecting that

another safety feature will protect you. In the incident described above,

if proper lamps were used, the ballast could still have been defective

from other causes. Also, GFCIs can be defective. That is why they

should be periodically tested.

7) Check that power cords are in good condition.

8) Do not use extension cords as a substitute for permanent wiring.

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Electrical Work

Electrical work is only to be performed by

qualified individuals

Contact Facilities X4588 for ALL electrical work

Do not attempt to fix on your own

Attempting to repair equipment

yourself may create a hazard

Conclusion

Know and follow safe work rules and practices

NO EXTENSION CORDS AS PERMANENT

WIRING

POWER STRIPS ARE FOR ELECTRONICS

ONLY

Report all unsafe conditions to Facilities X4588

or EHS X4078