Section 1 - Safety Precautions - Read Before Using; Symbol Usage; Arc Welding Hazards - Miller Bobcat 250 Owner's Manual

SECTION 1 – SAFETY PRECAUTIONS – READ BEFORE USING
Protect yourself and others from injury—read, follow, and save these important safety precautions and operating instructions.
1-1.

Symbol Usage

DANGER! – Indicates a hazardous situation which, if not
avoided, will result in death or serious injury. The possible
hazards are shown in the adjoining symbols or explained
in the text.
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury. The possible haz-
ards are shown in the adjoining symbols or explained in
the text.
NOTICE – Indicates statements not related to personal injury.
1-2.

Arc Welding Hazards

The symbols shown below are used throughout this manual
to call attention to and identify possible hazards. When you
see the symbol, watch out, and follow the related instruc-
tions to avoid the hazard. The safety information given be-
low is only a summary of the more complete safety
information found in the Safety Standards listed in Section
1-7. Read and follow all Safety Standards.
Only qualified persons should install, operate, maintain,
and repair this equipment. A qualified person is defined as
one who, by possession of a recognized degree, certificate,
or professional standing, or who by extensive knowledge,
training and experience, has successfully demonstrated
ability to solve or resolve problems relating to the subject
matter, the work, or the project and has received safety
training to recognize and avoid the hazards involved.
During operation, keep everybody, especially children,
away.
ELECTRIC SHOCK can kill.
Touching live electrical parts can cause fatal
shocks or severe burns. The electrode and work
circuit is electrically live whenever the output is on.
The input power circuit and machine internal cir-
cuits are also live when power is on. In semiauto-
matic or automatic wire welding, the wire, wire
reel, drive roll housing, and all metal parts touching
the welding wire are electrically live. Incorrectly in-
stalled or improperly grounded equipment is a
hazard.
� Do not touch live electrical parts.
� Wear dry, hole-free insulating gloves and body protection.
� Insulate yourself from work and ground using dry insulating mats
or covers big enough to prevent any physical contact with the work
or ground.
� Do not use AC weld output in damp, wet, or confined spaces, or if
there is a danger of falling.
� Use AC output ONLY if required for the welding process.
� If AC output is required, use remote output control if present on
unit.
� Additional safety precautions are required when any of the follow-
ing electrically hazardous conditions are present: in damp loca-
tions or while wearing wet clothing; on metal structures such as
floors, gratings, or scaffolds; when in cramped positions such as
sitting, kneeling, or lying; or when there is a high risk of unavoid-
able or accidental contact with the workpiece or ground. For these
conditions, use the following equipment in order presented: 1) a
semiautomatic DC constant voltage (wire) welder, 2) a DC manual
(stick) welder, or 3) an AC welder with reduced open-circuit volt-
age. In most situations, use of a DC, constant voltage wire welder
is recommended. And, do not work alone!
�
Indicates special instructions.
This group of symbols means Warning! Watch Out! ELECTRIC
SHOCK, MOVING PARTS, and HOT PARTS hazards. Consult
symbols and related instructions below for necessary actions to
avoid the hazards.
� Do not connect to any electrical distribution system normally sup-
plied by utility power unless a proper transfer switch and ground-
ing procedure are employed.
� Disconnect input power or stop engine before installing or servic-
ing this equipment. Lockout/tagout input power according to
OSHA 29 CFR 1910.147 (see Safety Standards).
� Properly install, ground, and operate this equipment according to
its Owner's Manual and national, state, and local codes.
� Always verify the supply ground — check and be sure that input
power cord ground wire is properly connected to ground terminal
in disconnect box or that cord plug is connected to a properly
grounded receptacle outlet.
� When making input connections, attach proper grounding conduc-
tor first — double-check connections.
� Keep cords dry, free of oil and grease, and protected from hot met-
al and sparks.
� Frequently inspect input power cord and ground conductor for
damage or bare wiring — replace immediately if damaged — bare
wiring can kill.
� Turn off all equipment when not in use.
� Do not use worn, damaged, undersized, or repaired cables.
� Do not drape cables over your body.
� If earth grounding of the workpiece is required, ground it directly
with a separate cable.
� Do not touch electrode if you are in contact with the work, ground,
or another electrode from a different machine.
� Use only well-maintained equipment. Repair or replace damaged
parts at once. Maintain unit according to manual.
� Do not touch electrode holders connected to two welding ma-
chines at the same time since double open-circuit voltage will be
present.
� Wear a safety harness if working above floor level.
� Keep all panels and covers securely in place.
� Clamp work cable with good metal-to-metal contact to workpiece
or worktable as near the weld as practical.
� Insulate work clamp when not connected to workpiece to prevent
contact with any metal object.
� Do not connect more than one electrode or work cable to any sin-
gle weld output terminal. Disconnect cable for process not in use.
� Use GFCI protection when operating auxiliary equipment. Test
GFCI receptacles at high speed.
SIGNIFICANT DC VOLTAGE exists in inverter power sources
AFTER stopping engine.
� Stop engine on inverter and discharge input capacitors according
to instructions in Manual before touching any parts.
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