Electrical safety potection

1. ELECTRICAL SAFETY
AND PROTECTION

2. What 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.

3. Overcurrent 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

4. 12
 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

5. 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

6. 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
EXTENSION
CORD IS USED
WITH POWER
STRIP

7. Cord plug with ground prong missing
Damaged TVSS rated power strip
Adapter enables circuit overload
Not Permitted:

8. Not Permitted:
Lamp extension cord, also damaged
Power taps
Adapter to change 3-prong plug
to 2-prong eliminating ground

9. 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.

10. 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

11.  The following is an example of :
Electrocution Due to Improper Use of Common
Equipment

12. 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.

13. 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.

14. 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.

15. 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.

16. 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.

17. 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.

18. 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.

19. 13
 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

20.  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

21.  Rudra Pavan 130170111095
 Vijendra Rathor 130170111092
 Jaydev Rathva 130170111091
 Moin Quereshi 130170111089
 Ratansingh Sisodiya 130170111106