Safety in Welding, Cutting, and Allied Processes

ANSI Z49.1:1999
normal in dc or 1, 1.41, 1.73, or 2 times normal on ac
machines. Similar voltage differences will exist if both ac
and dc welding are done on the same structure.
11.4 Operation E11.4 This section applies to all arc welding and cutting
processes. For gas shielded arc welding, see also recommended
practice documents such as ANSI/AWS C5.6-89,
Recommended Practices for Gas-Metal Arc Welding.
11.4.1 Worker Instruction. Workers assigned to
operate or maintain arc welding equipment shall be acquainted
with those parts of this standard applicable to
their work assignments.
11.4.2 Checking Connections. After assembling any
connection to the machine, each assembled connection
shall be checked before starting operations to ascertain
that it is properly made. In addition, the work lead shall be
firmly attached to the work; magnetic work clamps shall
be freed from adherent metal particles and spatter on contact
surfaces.
11.4.3 Machine Frame Grounding. Grounding of the
welding machine frame shall be checked. Special attention
shall be given to safety grounding connections of portable
machines. See NFPA 70, National Electric Code ¤ , Article
250, Grounding.
11.4.4 Leaks. There shall be no leaks of cooling water,
shielding gas, or engine fuel that can adversely affect the
welders safety.
E11.4.1 Those sections of particular interest are Section
4, Protection of Personnel; Section 5, Ventilation; and
Section 6, Fire Prevention and Protection.
E11.4.2 Clean and tight connections are necessary to
prevent local heating. Properly insulated and dry connections
are necessary to prevent stray electrical currents and
possible shock or short circuits.
Coiled welding cable should be kept to a minimum and
any excess is to be spread out before use to avoid overheating
and damage to insulation. Jobs alternately requiring
long and short cables should be equipped with insulated
connectors so that idle lengths can be disconnected when
not needed.
E11.4.4 Moisture can carry electric current and increase
the chance of electric shock, shielding gases can cause
asphyxiation, and fuels can cause explosions or fires.
11.4.5 Safe Operating Instructions. Written rules and
instructions covering the safe operation of equipment shall
be made available to the welder and shall be strictly
followed.
11.4.6 Work Interruptions. When the welder leaves
the work or stops for an appreciable time, the equipment
or machine output shall be turned off or de-energized.
11.4.7 Moving the Machine. When the machine is to
be moved, the input power supply to the equipment shall
be electrically disconnected.
11.4.8 Equipment Not in Use. When not in use, metal
and carbon electrodes shall be removed from holders to
eliminate danger of electrical contact with persons or conducting
objects. When not in use, electrode holders shall
be so placed that they cannot make electrical contact with
persons, conducting objects, such as metal or wet earth,
flammable liquids, or compressed gas cylinders. When not
is use, guns of semiautomatic welding machines shall
be˚placed so that the gun switch cannot be operated
accidentally.
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