This document provides an overview of electrical safety. It discusses common causes of electrical fires such as defective devices and circuit overloading. It then covers important electrical safety topics like grounding, overcurrent protection devices like fuses and circuit breakers, GFCIs, proper and improper use of power strips and extension cords, damaged/unapproved devices, container bonding/grounding, and responsibilities of facilities and users. An example incident of electrocution from improper equipment use is also described to illustrate the importance of electrical safety.

1. ELECTRICAL SAFETY
AWARNESS TRAINING
Training Program
Updated 5/5/04

2. 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:
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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

3. Grounding
What is Grounding?

“Grounding” a tool or electrical system means intentionally creating a lowresistance 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.

4. Protection
Overcurrent Protection

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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

5. Power Extension Cords and Power
Strips

Extension 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
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6. 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

7. Improperly Used Power Strip
EXTENSION
CORD IS USED
WITH POWER
STRIP
EXAMPLES 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

8. Damaged and Unapproved Devices
Not Permitted:
Cord plug with ground prong missing
Damaged TVSS rated power strip
Adapter enables circuit overload

9. Damaged and Unapproved Devices
Not Permitted:
Lamp extension cord, also damaged
Power taps
Adapter to change 3-prong plug
to 2-prong eliminating ground

10. Container Bonding and Grounding
(Static Electricity)
Bonding Cable
Grounding Cable
Grounding Bus
or Electrode
7
• 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.

11. 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

12. Electrical Safety Incidents

The following is an example of :
Electrocution Due to Improper Use of
Common Equipment

13. 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.

14. The Incident
Dr. X adjusted the timer so that the lights would
be on and plugged the timer into a standard 3prong 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.

15. The Investigation
The investigation revealed the following details:
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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.

16. 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.

17. Preventing this Fatality
As with many very serious accidents, a number of factors were involved, any
one of which could have prevented this fatality.
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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.

18. 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.

19. …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.

20. Electrical Work

Electrical work is only to be performed by
qualified individuals
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Contact Facilities X4588 for ALL electrical work
Do not attempt to fix on your own
Attempting to repair equipment
yourself may create a hazard
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21. Conclusion
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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