Electrical
safety
Electrical
energy is of vital importance to many industries.
Some people work with electricity directly eg, engineers
and electricians, while others work with it indirectly
eg, office workers. Of all energy sources, electricity
has the greatest potential to seriously injure or
cause fatalities. The human body is an excellent
conductor of electricity and even non-fatal electric
shocks can cause severe and permanent injury.
Electrical
injuries include burns, electrocution and shock
(which can result in the loss of limb function and
neurological disorders).
Electrical
hazards in the workplace
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The
main hazards are:
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contact
with live parts |
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electrical
faults causing fires |
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fires or
explosions where electricity is the source of ignition. |
Electrical shock can arise from exposed contacts, live electrical
equipment, damaged insulation and wet conditions.
Electrical
fire can arise from loose connections, heating equipment,
short circuits and the use of incorrect electrical equipment
in hazardous environments.
Legal requirements
and standards
EnergySafe (Ministry of Economic Development) is a new programme of
legislative change that aims to clarify who is responsible
for workplace safety in the electrical and gas industries.
It is designed to provide reliable, consistent public and
product safety for electricity and gas, and to ensure that
workers in these areas are competent.
There
are various standards relating to electrical equipment and
installations. See Standards
New Zealand for specific information.
Safe work practices
Managing
electrical safety in the workplace
Employers
must carry out a risk assessment to identify potential workplace
electrical hazards and to access the likelihood of injuries
from the exposure to these hazards. This will enable appropriate
control measures to be implemented.
General precautions
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An
accessible and clearly identified switch near each fixed
machine to cut off power in emergency is provided. |
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For
portable equipment, socket-outlets are close by so that
equipment can be easily disconnected in an emergency. |
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Electrical
equipment used in flammable/explosive atmospheres
should be designed to stop it from causing ignition. |
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Double
adaptors and 'piggy back plugs' are not used. |
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The
wattage of all bulbs in light fixtures and lamps are
checked to make sure they are the correct wattage. Replace
bulbs that have a higher wattage than recommended to
prevent overheating that could lead to a fire. |
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Lightbulbs
and other equipment which could easily be damaged in
use are protected. There is a risk of electric shock
if they are broken. |
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Suspect
or faulty equipment is taken out of use, labelled 'DO
NOT USE' and kept secure until examined by a competent
person. |
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Where
possible, tools and power socket-outlets should be switched
off before plugging in or unplugging. |
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Equipment
is switched off and/or unplugged before cleaning or
making adjustments. |
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There
is provision for all equipment to be stored carefully,
securely and safely. |
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Workers
using electrical equipment are trained and supervised. |
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Electrical
installations are safe eg, by providing enough power
outlets. |
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Worn
or frayed cords are replaced. |
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Leads,
wiring and cables are in good condition and
in the correct position. |
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PVC
insulation tape should not be used to repair damaged
cords. Have the cords replaced. |
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Machinery
is unplugged before cleaning. |
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Enough
socket outlets are providing – overloading socket
outlets by using adaptors can cause fires. |
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All
connections to power points are made using the
correct plugs. |
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Isolating
transformers and residual current devices (RCD)
are used. |
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The
electricity supply is isolated from earth and
has a voltage between conductors not exceeding
230 volts. |
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No
part of a crane, digger, excavator, drill rig
or other mechanical plant, structure or scaffold
is brought closer than 4 metres to an overhead
line without the written consent of the powerline
owner. |
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Equipment
suitable for the working environment is used,
eg, cordless tools for wet and damp conditions. |
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Electrical
tools and equipment are inspected prior to their
first use by a qualified person and thereafter
at three monthly intervals. |
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All
tools and equipment have an identification tab
stating the date of last inspection and when
the next inspection is due. |
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Residual Current Devices (RCDs)Safe Work Practices
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Electrical
extension cords connected to power tools require the
use of a Residual Current Device (RCD) or Isolating
Transformer. |
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If
the RCD trips, it is a sign of a fault. Check the system
before using it again. |
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A
RCD is a valuable safety device, never bypass it. |
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A
RCD is not a "cure-all" for poor work practices. |
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Workers
should know how to test any portable RCD they are about
to use and tests should be carried out before using
the equipment. If they are not working properly, withdraw
from use immediately. |
Equipment intended to be protected by a RCD
This
should only be considered as an indication and must not
be taken as exhaustive.
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Hand
held electric power tools, such as drills, saws and
similar equipment. |
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Tools
such as jack-hammers, electric lawn mowers. |
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Equipment
on construction sites. |
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Equipment
such as appliances which move while in operation, such
as vacuum cleaners and floor polishers. |
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Appliances
in wet areas such as kitchens, including kettles, jugs,
frying pans, portable urns, food mixers/blenders. |
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Hand
held appliances such as hair dryers, curling wands,
electric knives etc. |
Equipment
not intended to be protected by a RCD
This
list is to be considered as an indication only and must
not be taken as exhaustive. It refers mainly to equipment
which is 'plugged' into a socket outlet, but is not intended
to be moved during operation or moved from place to place
frequently.
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Desk top
computers, printers, monitors, clocks, desk lamps. |
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Wall mounted
airconditioners. |
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Medical
equipment where any RCD "trip" could be detrimental
to the health of the patient. The risk of electrical
shock, if the equipment is movable, should be minimised
by regular inspection and testing. |
Temporary
supply switchboards
Temporary
supply switchboards must:
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Be
fitted with isolating transformers or with earth
leakage devices. |
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Where
installed in outdoor locations, be constructed
so that safe operation is not impaired by the
weather. |
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Incorporate
a stand for the support of cables and flexible
extension cords. |
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Be
provided with a door and locking facility acceptable
to the electrical supply authority. |
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Have
a door designed and attached in a manner that will not
damage any flexible cord connected to the board and
which will protect the switches from mechanical damage. |
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Have
a sign of the door stating “KEEP CLOSED –
LEADS THROUGH BOTTOM”. |
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Have
an insulated slot in the bottom for the passage of leads. |
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Be
attached to a permanent wall or a permanent structure
that has been designed for the purpose. |
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Where
pole or post mounted, be fixed by means of coach screws
or bolts. |
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Check
to see that fuses are the correct size for the circuit.
Replacing a correct size fuse with a larger size fuse
can present a serious fire hazard. |
Underground
power cables
Always
assume cables will be present when digging in the street,
pavement or near buildings:
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Use
up-to-date service plans. |
Electrical
cords
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Extension
cords should not exceed 50 metres in length. |
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Check
extension cords for nick/cuts before each use. |
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The
ends of flexible cables should always have the outlet
shealth of the cable firmly clamped to stop the wires
(particularly the earth) pulling out of the terminals. |
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Check
for damaged insulation and plugs before use. |
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Always
pull out electrical cords by the plug not the
extension cord. |
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Report
faulty equipment immediately, tag and remove
from service. |
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Do
not put electrical cords in places where they
can cause trip hazards or be cut through. |
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Where
possible, cords should not cross aisles or passageways. |
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Put
cords away once you have finished with them. |
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Extension
cords should not be used while wound around storage
reels or on retractable reels. This increases the electrical
resistance in the cord, which can lead to overheating
and eventually fire. The cord should always be fully
extended. |
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Extension
cords should be inspected regularly by a certified electrician. |
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Keep
power cords away from water or liquids. |
First aid
The
following recommendations provide some general first aid
guidelines for electrical injuries:
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Do
not touch the victim while they are still in
contact with the source of electricity. |
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Turn
off the power or disconnect the appliance providing
the source of electricity. |
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If
the power cannot be turned off use non-conductive material,
such as a piece of wood or dry rope, to separate the
victim from the power source. |
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Do
not move the injured person unless there is immediate
danger. |
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If
breathing has stopped apply mouth-to-mouth resuscitation.
If there is no pulse, start cardiopulmonary resuscitation
(CPR). |
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If
burns have arisen, remove any clothing that comes off
easily, apply dry and sterile dressing and seek urgent
medical attention. |
Related links
For
further advice, the following links may be of help. Please
note that the standards of other countries will be different
from those in New Zealand. ACC does not endorse the advice
or take responsibility for the maintenance, updates and
content of these sites.
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