(23) Have you checked so that no external
(9) Is the equipment case connected to the
power or telephone lines off the premises are
work terminal of the secondary?
within the zone ?
(10) Is the wire used for this connection of
sufficient size ?
(24) Are the grounds driven ground rods ?
(11) Is the work terminal connected to a
(25) Is a cold water pipe used as ground?
good electrical ground ?
(26) If so, does it enter the ground 10 feet
(12) Is the cable or copper braid used for
or less from the connection ?
this connection equal to or greater in current
(27) Are the connections to the ground clean
carrying capacity than the welding lead ?
and tight ?
(13) Is this cable as short as possible?
(28) If operated within a metal building, is
(14) Are the spark gaps set at .008 inches or
the building properly grounded ?
If the answers to the above questions are affirma-
(15) Are all service and access doors closed
tive, the equipment may reasonably be expected
and bolted ?
to meet the radiation limits set by the Federal
(16) Are the welding leads less than 25 feet
(17) Are they as short as possible?
2-5. Equipment Conversion
(18) Are the welding leads on the floor or
a. General. The welding machine can operate
placed on a suitable board?
on either 208, 230 or 460 volts by the correct
(19) Are the welding leads approximately
positioning of the voltage change bars.
3/4 inch to 1 inch apart?
(20) Have you visualized the H.F.I. zone, a
b. Voltage Change Bar Positioning.
sphere with 50 feet radius centered on the weld
(1) R e m o v e t h e s c r e w s o n t h e v o l t a g e
change bar access panel and open door.
(21) Have the unshielded power and light
wires originally in this H.F.I. zone been placed
voltage change bars in the desired position.
in grounded shields or been relocated outside
Warning: Do not reposition voltage
the zone ?
change bars while power source is connected to
(22) Have all large metallic objects and any
the machine. To do so could cause a serious
long guy or supporting wires in the H.F.I.. zone
electrical shock and possible death.
been grounded ?