Miller Electric MC-80M - Manual (Page 3)

sr2 11/92
PLASMA ARC CUTTING SAFETY PRECAUTIONS
WARNING
PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH. KEEP CHILDREN
AWAY. PACEMAKER WEARERS KEEP AWAY UNTIL CONSULTING YOUR DOCTOR.
In cutting, as in most jobs, exposure to certain hazards occurs. Cutting is safe when precautions are taken. The
safety information given below is only a summary of the more complete safety information that will be found in the
Safety Standards listed on the next page. Read and follow all Safety Standards.
HAVE ALL INSTALLATION, OPERATION, MAINTENANCE, AND REPAIR WORK PERFORMED ONLY BY
QUALIFIED PEOPLE.
PLASMA ARC CUTTING can be hazardous.
CUTTING can cause fire or explosion.
Hot metal and sparks blow out from the cutting arc.
The flying sparks and hot metal, hot workpiece, and
hot equipment can cause fires and burns. Check and
be sure the area is safe before doing any cutting.
1. Protect yourself and others from flying sparks and hot metal.
2. Do not cut where flying sparks can strike flammable material.
3. Remove all flammables within 35 ft (10.7 m) of the cutting arc. If
this is not possible, tightly cover them with approved covers.
4. Be alert that sparks and hot materials from cutting can easily go
through small cracks and openings to adjacent areas.
5. Watch for fire, and keep a fire extinguisher nearby.
6. Be aware that cutting on a ceiling, floor, bulkhead, or partition can
cause fire on the hidden side.
7. Do not cut on closed containers such as tanks or drums.
8. Connect work cable to the work as close to the cutting area as
practical to prevent cutting current from traveling long, possibly
unknown paths and causing electric shock and fire hazards.
9. Never cut containers with potentially flammable materials inside
– they must be emptied and properly cleaned first.
10. Do not cut in atmospheres containing explosive dust or vapors.
11. Do not cut pressurized cylinders, pipes, or vessels.
12. Do not cut containers that have held combustibles.
13. Wear oil-free protective garments such as leather gloves, heavy
shirt, cuffless trousers, high shoes, and a cap.
14. Do not locate unit on or over combustible surfaces.
15. Remove any combustibles, such as a butane lighter or matches,
from your person before doing any cutting.
ELECTRIC SHOCK can kill.
Touching live electrical parts can cause fatal shocks
or severe burns. The torch and work circuit is
electrically live whenever the output is on. The input
power circuit and machine internal circuits are also
live when power is on. Plasma arc cutting requires
higher voltages than welding to start and maintain the
arc (200 to 400 volts dc are common), but also uses torches designed
with safety interlock systems which turn off the machine when the
shield cup is loosened or if tip touches electrode inside the nozzle.
Incorrectly installed or improperly grounded equipment is a hazard.
1. Do not touch live electrical parts.
2. Wear dry, hole-free insulating gloves and body protection.
3. Insulate yourself from work and ground using dry insulating mats
or covers big enough to prevent any physical contact with the
work or ground.
4. Do not touch torch parts if in contact with the work or ground.
5. Turn off power before checking, cleaning, or changing torch
parts.
6. Disconnect input power before installing or servicing this
equipment. Lockout/tagout input power according to OSHA CFR
1910.147 (see Safety Standards).
7. Properly install and ground this equipment according to its
Owner’s Manual and national, state, and local codes.
8. 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 – always
verify the supply ground.
9. When making input connections, attach proper grounding
conductor first.
10. Frequently inspect input power cord for damage or bare wiring –
replace cord immediately if damaged – bare wiring can kill.
11. Turn off all equipment when not in use.
12. Inspect and replace any worn or damaged torch cable leads.
13. Do not wrap torch cable around your body.
14. Ground the workpiece to a good electrical (earth) ground if
required by codes.
15. Use only well-maintained equipment. Repair or replace
damaged parts at once.
16. Wear a safety harness if working above floor level.
17. Keep all panels and covers securely in place.
18. Do not bypass or try to defeat the safety interlock systems.
19. Use only torch(es) specified in Owner’s Manual.
20. Keep away from torch tip and pilot arc when trigger is pressed.
21. Clamp work cable with good metal-to-metal contact to workpiece
(not piece that will fall away) or worktable as near the cut as
practical.
ARC RAYS can burn eyes and skin.
Arc rays from the cutting process produce intense
visible and invisible (ultraviolet and infrared) rays that
can burn eyes and skin.
1. Wear face protection (helmet or shield) with correct shade of filter
to protect your face and eyes when cutting or watching. ANSI
Z49.1 (see Safety Standards) suggests a No. 9 shade (with No. 8
as minimum) for all cutting currents less than 300 amperes.
Z49.1 adds that lighter filter shades may be used when the arc is
hidden by the workpiece. As this is normally the case with low
current cutting, the shades suggested in Table 1 are provided for
the operator’s convenience.
2. Wear approved safety glasses with side shields.
3. Use protective screens or barriers to protect others from flash
and glare; warn others not to watch the arc.
4. Wear protective clothing made from durable, flame-resistant
material (wool and leather) and foot protection.
NOISE can damage hearing.
Prolonged noise from some cutting applications can
damage hearing if levels exceed limits specified by
OSHA (see Safety Standards).
1. Use approved ear plugs or ear muffs if noise level is high.
2. Warn others nearby about noise hazard.
Table 1. Eye Protection For Plasma Arc Cutting
Current Level In Amperes Minimum Shade Number
Below 20
20 – 40
40 – 60
60 – 80
#4
#5
#6
#8