-8-
H8153 DC Stick/TIG Pulse Welder
Grounding for
Welding Safety
There are two or more electrical circuits involved
in any welding operation. The practice of safely
grounding these circuits is documented in vari-
ous codes and standards (refer to
Additional
Sources for Welding Codes and Standards
on
Page 6
).
Welding Machine Ground
When properly connected to a power source, the
Model H8153 welder is grounded through the
power cord and power grid. The internal welding
circuit of the welder is insulated from the external
enclosure. However, to avoid shocking hazards if
this internal insulation fails, you must establish a
separate earth ground for the welder's external
enclosure. This ground will ensure that if a short
does occur and the metal enclosure becomes
intergrated with the welding current, the current
will safely dissipate directly through the ground
instead of through you.
Note:
Refer to the publication NFPA 70, National
Electric Code, Article 250, Grounding, and your
local electrical codes for the correct method of
establishing this ground.
The grounding terminal for the Model H8153
external enclosure is located on the right rear of
the welder (see
Figure 5
).
Figure 5.
Location of external enclosure
grounding terminal on the rear of the Model
H8153.
Workpiece Ground
The incoming power circuit to the welder and the
working welding circuit are two separate circuits
that must have separate grounds. The weld-
ing circuit consists of the internal components
of the welder, the welding cables, the electrode
holder/torch assembly, the work clamp, and the
workpiece.
ANSI Welding Standards (Z49.1, 11.3.2.1) specify
that "Grounding [of the workpiece] shall be done
by locating the work on a grounded metal floor or
platen, or by connection to a grounded building
frame or other satisfactory ground."
Always ensure that the ground for the incom-
ing power circuit to the welder and the
ground for the working welding circuit are
never connected. Failure to comply with this
warning could result in death, serious per-
sonal injury, or property damage.
However, you must also avoid "double ground-
ing" the workpiece. ANSI Z49.1 states that "Care
shall be taken to avoid the flow of welding current
through a connection intended only for safety
grounding since the welding current may be of a
higher magnitude than the grounding conductor
can safely carry."
Note:
The work lead from the welder is some-
times incorrectly referred to as the "ground lead."
The work lead from the welder is NOT a ground.
The work lead and the ground connection to the
workpiece are separate and must NOT be con-
nected in any way.
TIG welders use a high frequency current
that creates a high electro-magnetic field
(EMF) around the welder. EMF disrupts elec-
tronic devices. To avoid damage, keep elec-
tronic devices at least 50 feet from the
welder when it is powered on. Workers who
have pacemakers must consult with their
physician before using this equipment or
being within 50 feet of welding operations.
