Page 128 - 6848

Some portable equipment requires substantial power to operate and may
require voltages higher than those usually used for portable tools, so that the current
is kept down to reasonable levels. In these cases, power leads with a separate earth
conductor and earth screen must be used. Earth leakage relays and earth monitoring

equipment must also be used, together with substantial plugs and sockets designed for
this type of system.
Electrical equipment is safe when properly selected, used and maintained. It is
important, however, that the environmental conditions are always carefully
considered.
The hazards associated with portable appliances increase with the frequency of
use and the harshness of the environment (construction sites are often particularly
hazardous in this respect). These factors must be considered when inspection, testing
and maintenance procedures are being developed.

 Secondary hazards

It is important to note that there are other hazards associated with portable
electrical appliances, such as abrasion and impact, noise and vibration. Trailing leads
used for portable equipment and raised socket points offer serious trip hazards and
both should be used with great care near pedestrian walkways. Power drives from
electric motors should always be guarded against entanglement hazards.
Secondary hazards are those additional hazards which present themselves as a
result of an electrical hazard. It is very important that these hazards are considered
during a risk assessment. An electric shock could lead to a fall from height if the
shock occurred on a scaffold or it could lead to a collision with a vehicle if the victim
collapsed on to a roadway.
Similarly an electrical fire could lead to all the associated fire hazards (e.g.
suffocation, burns and structural collapse) and electrical burns can easily lead to
infections.

14.3 Protection against E lectrical H azards

Most electrical accidents result from one of the following three factors:
 unsafe equipment or installation;
 unsafe environment;
 unsafe work practices.
Some ways to prevent these accidents are through the use of:
 insulation;
 guarding;
 grounding;

 electrical protective devices;
 safe work practices.
1) Insulators such as glass, mica, rubber, or plastic used to coat metals and
other conductors help stop or reduce the flow of electrical current. This helps prevent
shock, fires, and short circuits.

4