Do not touch
live electrical parts.
Live
electrical parts can include the power supply, the power and work cables, the
torch and the work itself (if the work is not connected to earth ground.)
Electric
shock can be avoided. Follow the recommended practices listed below. Faulty installation,
improper grounding, and incorrect operation and maintenance of electrical equipment
are always sources of danger.
Connect
electrical equipment and work piece correctly. Prevent electrical shock.
Connect
power supply and control cabinet chassis to approved earth ground.
Connect
work piece to “work” output connection of power supply.
Connect
work piece (as illustrated below) OR power supply work terminal (but not both)
to approved earth ground. “Double-grounding” can cause welding/cutting current
to occur in conductors intended only for safety grounding and can result in
destruction of the safety ground.
NOTE: The work lead
is NOT a ground lead; the work lead is to be used only to complete the welding circuit.
Make
good electrical connections of the work lead to the power supply work terminal
and to the work piece. A missing or poorly-connected work lead can cause a
fatal shock. Make sure the work lead is always in good condition.
Use
the correct cable size. Sustained overloading will cause cable failure and
result in possible electrical shock or fire hazard. Work cable should be the
same rating as the torch cable.
Make
sure all electrical connections are tight, clean, and dry. Poor electrical connections
can heat up, and even melt. They can also cause bad welds and produce dangerous
arcs and sparks. Do not try to make an electrical connection through paint. Do
not allow water, grease, or dirt to accumulate on plugs, sockets, or electrical
units.
Insulate
yourself from work piece and ground. Moisture and water can conduct electricity.
To prevent shock, it is advisable to keep work areas, equipment, and clothing
dry at all times. Fix water leaks immediately. Keep hoses from touching hot
metal. Do not exceed recommended water pressures. Make sure that you are well
insulated. Wear dry insulated gloves, rubber-soled shoes, or stand on a dry board
or platform.
Use
only the proper equipment if welding must be done in electrically-hazardous conditions.
Such conditions include damp or warm locations, wet clothing, metal structures
such as floors or scaffolds, cramped positions or wherever there is a high risk
of contact with work piece or ground. In any of these situations use:
DC
MIG welding
DC
manual (stick electrode) welding
AC
welder with reduced open-circuit voltage control
Keep
cables and connectors in good condition. Improper or worn electrical
connections can increase the chance of an electrical shock. Do not use worn,
damaged or bare cables.
Avoid
open-circuit voltage. Open circuit voltage of welding, cutting and gouging power
supplies can cause electric shock. When several welders are working with arcs
of different polarities, or when using multiple alternating current machines, the
open-circuit voltages can be additive, the added voltages increase the severity
of the shock hazard.
Remove
metal jewelry. It is recommended that rings, watches, necklaces, and other
metallic items be removed before welding or cutting. Accidental contact of jewelry
with welding power can cause metal to become hot or even melt. It can also
increase the possibility of a fatal shock.
Follow
recognized safety standards. Follow the recommendations in American National
Standard Z49.1, “Safety in Welding and Cutting,” available from the American
Welding Society, P. 0. Box 351040, Miami, FL 33135, and also the National Electrical
Code, NFPA No. 70, which is available from the National Fire Protection Association,
Battery march Park, Quincy, MA 02269.
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