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(III) Connectors
Fully insulated lock-type connectors should be used to join welding cable lengths.
(IV) Cables
Frequently inspect cables for wear, cracks and damage. IMMEDIATELY REPLACE
those with excessively worn or damaged insulation to avoid possibly lethal shock
from bared cable. Cables with damaged areas may be taped to give resistance
equivalent to original cable. Keep cable dry, free of oil and grease, and protected
from hot metal and sparks.
(V) Terminals and other exposed parts
Terminals and other exposed parts of electrical units should have insulating covers
secured before operation.
(VI) Electrode
a)
Equipment with output on/off control (contactor) Welding power sources for
use with the gas metal arc welding, gas tungsten arc welding and similar
processes normally are equipped with devices that permit on/off control of the
welding power output. When so equipped the electrode wire becomes
electrically HOT when the power source switch is ON and welding gun switch
is closed. Never touch the electrode wire or any conducting object in contact
with the electrode circuit unless the welding power source is off.
b)
Equipment without output on/off control (no contactor) Welding power sources
used with shielded metal arc welding and similar processes may not be equipped
with welding power output on/off control devices. With such equipment the
electrode is electrically HOT when the power switch is turned ON. Never touch
the electrode unless the welding power source is off.
(VII) Safety devices
Safety devices such as interlocks and circuit breakers should not be disconnected
or shunted out. Before installation, inspection, or service of equipment, SHUT
OFF all power and remove line fuses (or lock or red-tag switches) to prevent
accidental turning ON of power. Do not open power circuit or change polarity
while welding. If, in an emergency, it must be disconnected, guard against shock
burns, or flash from switch arcing. Always shut OFF and disconnect all power to
equipment. Power disconnect switch must be available near the welding power
source.
3-C Fire and Explosion Prevention
Comply with precautions in 2-C. Equipment’s rated capacity. Do not overload arc
welding equipment. It may overheat cables and cause a fire. Loose cable connections
may overheat or flash and cause a fire. Never strike an arc on a cylinder or other
pressure vessel. It creates a brittle area that can cause a violent rupture or lead to
such a rupture later under rough handling.
3-D Shock Prevention
Exposed hot conductors or other bare metal in the welding circuit, or in ungrounded,
electrically-HOT equipment can fatally shock a person whose body becomes a
conductor. DO NOT STAND, SIT, LIE, LEAN ON, OR TOUCH a wet surface when
welding, without suitable protection.
3-E Protection for Wearers of Electronic Life Support Devices
(Pacemakers).
Magnetic fields from high currents can affect pacemaker operation. Persons wearing
electronic life support equipment (pacemaker) should consult with their doctor before
going near arc welding, gouging, or spot welding operations.
3-F To Protect Against Shock:
Keep body and clothing dry. Never work in damp area without adequate insulation
against electrical shock. Stay on a dry duckboard, or rubber mat when dampness or
sweat can not be avoided. Sweat, sea water, or moisture between body and an
electrically HOT part - or grounded metal - reduces the body surface electrical
resistance, enabling dangerous and possibly lethal currents to flow through the body.
(I) Grounding the equipment
When arc welding equipment is grounded according to the National Electrical
Code, and the work is grounded, a voltage may exist between the electrode and
any conducting object. Examples of conducting objects include, but are not limited
to, buildings, electrical tools, work benches, welding power source cases,
workpieces, etc. Never touch the electrode and any metal object unless the welding
power source is off. When installing, connect the frames of each unit such as
welding power source, control, work table, and water circulator to the
building ground. Conductors must be adequate to carry ground currents safely.
Equipment made electrically HOT by stray current may shock, possibly fatally.
Do NOT GROUND to electrical conduit, or to a pipe carrying ANY gas or a
flammable liquid such as oil or fuel.
(II) Electrode holders
Fully insulated electrode holders should be used. Do NOT use holders with
protruding screws or with any form of damage.
