Electric Shock from Electric
Shock to a welder might be assumed to
be an acceptable practice due to the frequency of shocks to welders caused by improper
personal protection and awareness. This belief can and has been a fatal assumption.
Many welders have suffered shocks and
have only experienced an unpleasant tingle, but muscle spasms from even a mild shock may
lead to a fall from a height or cause heart problems which are not readily noticeable
or in certain circumstances cause death by electrocution.
- The main causes for death or serious
injury while welding are as follows:
- Poorly maintained or badly connected
- Shock, from both the welding machine
incoming power and the welding voltages.
- Burn, from flash at the welding
machine incoming power cable & connections.
When performing manual arc welding there
is a significant potential for the welder to receive a shock by simultaneously touching
the electrode and work piece. This is due to the fact the electrode is changed while the
electrode holder is electrically live. Fuses or earth leakage contact breakers do not
protect the welder from such a hazard. The potential for electrical shock increases with
Shock can be avoided by using proper
welding techniques and PPE. Training welders in the electrical hazards of welding and
electric welding machines is a requirement of OSHA 1910. Training will greatly reduce
the myth that being shocked is an acceptable practice and it will prevent injury or death.
Factors, Which Affect The Risk And
Severity Of The Shock
- Set voltage (OCV) of the welding
- Use of alternating or direct current
(ac. is 2 to 3 times more dangerous than dc)
- Moisture from rain, perspiration,
or other source;
- How well the welder is insulated
from the electrode and the work piece;
- Which parts of the body are in
contact with the work and the electrode. Current flow between the left hand and the
torso is the most dangerous.
- Whether the welder has to work
in physical contact with the work piece, particularly in a cramped (kneeling, sitting
or lying) position such as inside vessels, pipes, and structural components. The electrically
hazardous environment does not need to be a confined space.
Work Methods To Reduce The Risk Of
When a workplace hazard assessment is
conducted, ensure the risk of such electric shock is considered and appropriate measures
are taken to minimize the risk.
- The use of dry, hole free welding
gloves on both hands while welding, particularly when changing electrodes should be
compulsory and be a written safety policy.
- Remove stub ends immediately after
welding; do not leave an electrode holder with a stub end in it.
- Turn off the power at end of each
shift or when taking a break. Do not drag live leads to the work.
- Leather covered cushions, leather
aprons, leather jackets, heat-resisting blankets should be used to cover those parts
of the work piece, which the welder may contact.
- In hot conditions the risk of electrocution
is increased because of clothing and equipment being soaked in perspiration. The risk
is far worse in closed environments, such as tanks or vessels. Take frequent rest
periods, during which time dry off equipment and clothing. Frequently change or alternate
gloves and protective clothing to avoid perspiration accumulating. Ventilate or if
possible air-condition the work air. Ventilation will help dry perspiration and cool
the body. Cool the face with an air mask. If clothing (including gloves) becomes soaked
with perspiration, it must be changed.
- If it is not possible to keep it
dry, the environment must be considered extremely dangerous. Either a voltage limited
welding power source should be used, or a contactor switch on the torch should control
Equipment Checks to Avoid Shock
- Never attempt disconnecting of
power receptacle when the main disconnect switch is on (energized).
- Inspect the welding leads a prior
to use to ensure that the insulation is not damaged and that the conductor is not
- Ensure the welding leads are connected
to the welding machine by a male plug and that the female portion of the connector
is the energized part of the set.
- Ensure the welding lead connection
points on the welding machine are shielded to avoid accidental contact with exposed
- Turn off welding machine in some
cases until the welder is in position to make a weld. (In cases where the welder must
lie/lean on a grounded surface to perform a welding task another person should start
the machine when the welder is ready to strike an arc and begin the task.)
- Eliminate the possibility of partially
exposing a connection while pulling the leads; male and female connectors of welding
leads may need to be taped or otherwise restrained form separating. Welding leads
should not be tied in a knot.
- Inspect rod holders for cracked
or broken insulated covers, discard or repair insulation if found defective.
Comment: I don't know the source of this paper, but felt it might be useful