SECTION V: SAFE
WORK PRACTICES
(Understand the Hazards of Your Work
Environment)
Information presented is not intended to be
comprehensive or all inclusive; contact your supervisor, safety officer, or the
Environmental Health and Safety Office, 475-7041, for assistance or further
information on any given topic.
ELECTRICAL SAFETY
The low current that lights a Christmas tree bulb is
enough to kill you if it passes through your heart and lungs! While electricity is the most widely used
source of power in industry, all electrically powered equipment (as well as the
electrical distribution system itself) is potentially hazardous. Unfortunately, the potential destructiveness
of electricity is also commonly ignored and underrated.
Electrical accidents in the workplace kill more than
1,000 persons every year, and injure far more.
Accidental contact with electrical current as low as
120 volts can cause arcs, shock, severe burns, or fires and explosions. And slight shocks not causing direct injury
may jolt you into a secondary accident -- you could fall from a ladder or lose
control of a power tool. Most of these
accidents are preventable.
When working on circuits of any voltage, you can protect
yourself from electrical harm if you wear proper personal protective equipment,
use the correct tools and equipment, inspect and maintain them regularly, and
follow safe work procedures.
An electrical injury occurs when your body becomes a
conductor -- part of the path that an electrical current takes to a
ground. People, water, trees, damp earth
and metal are excellent conductors. An
insulator is the opposite of a conductor, and resists the flow of electrical
current. Some effective insulators are
rubber, plastic, dry wood or glass.
In addition to personal injuries, overheating of
electrical equipment and arcs resulting from short circuits in improperly
installed or maintained electrical equipment are two of the primary causes of
fire in facilities.
The causes of most electrical accidents can be traced
to:
1.
unsafe work
practices
2.
defective
equipment
3.
lack of
training/knowledge of the dangers of electricity, or any combination of these
three
One study of accidents in
ELECTRICAL SAFETY SUGGESTIONS
1.
Treat all
electrical equipment as if it is "live."
2.
Unplug machinery
and appliances before inspecting, cleaning, repairing or removing anything from
them.
3.
Check over your
equipment, cords and attachments before each use. To avoid shorts, shocks and fires, never use
an appliance that has a frayed cord. If
you know something is broken, don't use it!
4.
Avoid work
practices which overload motors, insulation, wires or electrical
accessories. Avoid overloading of
circuits or over-fusing circuits by the use of the wrong size or type of fuse.
5.
Use only
UL-listed appliances, equipment and tools.
6.
Know the location
of fuses and circuit breakers; never bypass safety interlocks such as circuit
breakers, fuses, etc. Replace blown
fuses only with fuses of the same design and capacity.
7.
Practice good
housekeeping and keep electrical equipment and work areas clean. Around electricity, substances such as oil,
dust, waste and water can all create fire hazards.
8.
Do not permit
open conduits, switch boxes, damaged or worn connections, and exposed live
wires; report/repair immediately if any of these conditions exist.
9.
Know the location
of the closest "Class C" fire extinguisher for electrical fires.
Never use water!
10.
Make it a habit,
when working around electrical equipment, to identify all conductors that could
come in contact with electricity (e.g., metal tools, pipes, ladders, etc.).
11.
Always maintain a
clearance of at least 30 inches to provide clear access to electrical
panels. Be sure switch panels and boxes
are properly labeled.
12.
If working
outdoors, carefully check the area before you begin work to identify and avoid
overhead hazards, such as those posed by power lines. Be especially careful in these situations if
you must handle long, conductive materials (e.g., pipes, metal rods,
ladders). Ladders used in these
situations should be made of nonconductive material.
ELECTRICAL ACCESSORIES (e.g., cords,
receptacles, plugs, wiring, etc.)
1.
Never use
temporary wiring.
2.
Do not overload
circuits. Never overload electric
outlets with too many plugs.
3.
Avoid using
extension cords, especially to permanently connect a light or appliance. If an extension cord must be used, don't
exceed its recommended rating, don't plug two extension cords together, and
don't place the cord beneath a rug.
4.
Never use light
duty, ungrounded extension cords for industrial service; avoid the use of
extension cords in place of permanent wiring extensions.
5.
Do not use
extension cords to operate stationary equipment or other permanent operations.
6.
Always insert
plugs straight into the receptacle. Disconnect electric cords by pulling on the
plug -- not yanking or pulling on the cord.
7.
All extension cords
for tools and appliances must be three-wire parallel ground with grounding lug
plugs. Never remove a ground connection
(e.g., never snap off the grounding prong to make the plug fit a two-prong
receptacle -- take the time to get an adapter plug).
8.
Route cords away
from traffic areas (otherwise, they may cause both a tripping hazard and a fire
hazard!).
9.
Be sure
receptacles are mounted firmly in their enclosures, without movement when the
plug is inserted. Loose receptacles can cause short circuits. Replace damaged or broken wall plates to
avoid accidental contact with energized parts.
ELECTRICAL EQUIPMENT AND MACHINERY
1.
Guards on
equipment and machinery are designed to provide protection from energized
parts. They should never be removed or
modified.
2.
Equipment
operators should be familiar with the limitations of their equipment and
trained to observe and report abnormal conditions.
3.
Be sure that all
motors are equipped with magnetic switches to prevent automatic restart after
shutdown.
4.
Be sure to turn
off equipment before leaving a work area.
5.
Replace equipment
with broken housing and loose or vibrating machine parts before using the
equipment.
6.
Don't permit
dirty motor windings, improperly adjusted brushes, worn commutators,
broken housings, loose or vibrating machine parts. Turn in defective equipment, and use only
grounded equipment approved by the Underwriters Laboratory (UL) for the
intended use. If there is any doubt about the condition or function of any
electrical equipment one may have to use, get help from authorized and trained
personnel instead of taking a chance.
7.
De-energize, lockout and tag equipment or circuits for cleaning or
repair. Wear the protective equipment
you're supposed to, but don't presume it replaces common sense, and don't rely
on protective equipment alone to provide protection during electrical
installation and repair.
8.
Never tamper with
utility equipment.
9.
Whenever
possible, stand on rubber mats or wooden floors when working on electrical
equipment and wear protective gloves and hat.
10.
Avoid using
electrical equipment when you or the equipment is wet. If you must work in a damp area, use a ground
fault circuit interrupter (GFCI). Stay
off metal ladders whenever you are doing electrical work; select a
non-conductive ladder instead.
ELECTRICALLY POWERED HAND TOOLS, APPLIANCES AND OTHER
PORTABLE EQUIPMENT
1.
If you have a
choice of power tools, select the double-insulated kind. Then regularly inspect to ensure that
insulation is not defective, inadequate, worn, frayed, wet, oily or
deteriorated; any of these conditions could create short circuits and energize
equipment frames.
2.
Ensure that all
stationary and portable electric tools are properly connected and grounded
according to manufacturer's specifications (except double insulated tools).
3.
When using
portable electrical equipment, make sure the power switch is off before
plugging in the equipment. Always start
and end the equipment from "OFF;" turn the equipment off before
unplugging.
4.
Never insert a
metal object into an appliance (e.g., a toaster).
5.
Never carry an
appliance by its cord.
6.
Avoid use of
power tools in damp or wet areas; check for GFCIs.
7.
Inspect power
tools for cracks or breaks in the housing. Tag defective tools for replacement
or repair.
8.
Check plugs and
cords for defects like kinks, damaged insulation, exposed wire strands, and
missing, loose, or bent prongs. Prior to
use, repair or replace any that are found to be
damaged. Never modify a plug by bending
or removing the blades.
9.
If an appliance
smokes, sparks or gives a shock at any time, unplug it and have it repaired
before using it again.
10.
If an appliance
catches fire, don't touch the appliance.
Use a fire extinguisher rated for "Class C" fires (or baking
soda) to put out the fire. Never use
water on an electrical fire (it can cause an electrical shock).
ELECTRICAL SAFETY OUTDOORS: (Courtesy
Washington Water Power Company,
1.
Stay away from
substation fences and electrical equipment; they contain high voltage and
should be considered dangerous.
2.
Never climb trees
near power lines, and never climb a utility pole for any reason.
3.
Always assume
that overhead power lines are "hot."
Never work within 10 feet of a power line. Look up and live: when working outside with ladders, antennas,
irrigation pipe or long-handled tools, always check to see if power lines are
near.
4.
Teach children
electrical safety. Caution them against
climbing trees and flying kites and model planes near power lines. If a flying toy is caught on the lines, they
should not try to retrieve it. An object
entangled in a power line can become a conductor, allowing electricity to flow
down to the person holding the other end of the object.
5.
Metallic (mylar) balloons are highly
conductive and should be kept indoors.
6.
When using power
tools or electric lawn mowers, keep the cord behind you where it won't be
cut. Sturdy rubber-soled shoes or boots
are recommended for your protection.
7.
Be sure tools and
extension cords are suitable for outdoor use and plugged into outlets equipped
with ground fault circuit interrupters (GFCIs).
8.
When operating a
backhoe, crane or other heavy construction equipment, use another person as a
spotter to make sure you keep 10 feet away from power lines. If you have questions about de-energizing the
line, call your local electrical utility company. Keep children away from the equipment at all
times.
9.
Before doing any
digging on your property, especially major projects like foundations or post
holes, first contact the underground utility location service in your
area. One misplaced dig with a shovel,
auger or backhoe could strike a buried electric, gas or other utility line.
10.
If you see a
downed line, call the power company immediately. Always assume a downed line is energized
("hot") and don't touch it or attempt to move it.
11.
Never try to move
a person or object that is touching a downed line, or you may become a victim
as well.
12.
Metal fences and
other objects can become electrified when a live power line falls on them. Stay away.
13.
If a power lines
hits your car, stay inside unless you are in immediate danger from fire. If you are forced to leave the vehicle while
it is in contact with a power line, jump as far as you can, landing with both
feet together and ensuring that no part of your body touches the vehicle and
ground at the same time. Hop or shuffle
away from the vehicle so your feet remain together. Don't return to the vehicle until the power
company says it is safe.
INSPECT YOUR AREA AND EQUIPMENT FOR ELECTRICAL HAZARDS
Take nothing for granted -- a "head's up"
attitude is your best protection in electrical matters.
Visual inspections:
Most electrical defects and hazardous conditions can be detected by
simple visual inspections. Electrical
wiring (permanent and temporary) and fixed electrical equipment should be
included in the inspection program.
Unsafe work conditions you should look for, report and correct include:
1.
improperly
grounded equipment (ground wires missing or broken, bad connection); loose
connections on equipment
2.
shocking,
sparking, overheating or smoking machinery; electrical arcing;
"tingling" sensation when using a power tool; unusual noise or
vibration
3.
extension cords
in permanent use; unprotected cords in walkways; light duty cords used where
heavy ones are needed; defective extension cords which should be replaced
4.
use of temporary
wiring in place of permanent wiring
5.
use of unauthorized or damaged temporary wiring (i.e.,
ungrounded or improperly spliced extension cords, light duty wiring used for
heavy equipment, etc.)
6.
exposed wiring or
sockets, broken plugs or outlets, snapped-off ground prongs, missing box covers
or faceplates
7.
switch boxes,
junction boxes, or conduits which are not properly covered or closed
8.
insulation which
is defective, inadequate, worn, frayed, wet, oily, or deteriorated
9.
corroded outlets,
switches and junction boxes
10.
defective
switches, receptacles, lamp sockets, tools or equipment (repair immediately, or
properly mark and make inoperable)
11.
bypassed circuit
breakers or fuses
12.
wet or damp
areas: outlets in damp areas without Ground Fault Circuit Interrupters (GFCI)
13.
explosion and
fire hazards near operating electrical equipment (trash, oil, dust, water,
flammable vapors, liquids or gases, corrosive chemicals); check for sealed
safety lights and explosion-proof equipment
14.
obstructed access
to panels and junction boxes; unlabeled panels and boxes
15.
overloaded
circuits; over-fused circuits (fuses wrong size or type)
16.
the presence of a
"Class C" extinguisher for electrical fires
17.
broken housings
(breaks, cracks, missing screws or bolts, etc.), loose or vibrating machine
parts, missing guards, defective insulation
18.
machinery left on
by previous worker
19.
untagged
machinery under repair
20.
presence of dust, dirt, water, chemicals or debris on or around
motors, transformers, distribution panels, etc.
IN SUMMARY:
An adequate program for the elimination of electrical
hazards and the prevention of electrical accidents will rely upon:
·
intelligent
selection and purchase of equipment and accessories
·
correct
installation of equipment
·
ongoing training
and education of employees
·
regular
inspection of equipment
· an established maintenance program