Jet MT Series, Operating Instructions Manual, Page: 9 / 32

9
7.0 Electrical connections
Electrical connections must be
made by a qualified electrician in compliance
with all relevant codes. This machine must be
properly grounded to help prevent electrical
shock and possible fatal injury.
7.1 GROUNDING INSTRUCTIONS
In the event of a malfunction or breakdown,
grounding provides a path of least resistance for
electric current to reduce the risk of electric shock.
The trolley power cord must be correctly wired into
the hoist, and the hoist power cord must be fitted
with an appropriate UL/CSA listed plug, or can be
“hard-wired” directly to a control panel. If hard-
wired, make sure a disconnect is available for the
operator.
If a plug is installed, it must have an equipment-
grounding conductor and a grounding prong. The
plug must be plugged into a matching outlet that is
properly installed and grounded in accordance with
all local codes and ordinances. Do not modify the
plug.
Improper connection of the equipment-grounding
conductor can result in a risk of electric shock. The
conductor with insulation having an outer surface
that is green with or without yellow stripes is the
equipment-grounding connector. If repair or
replacement of the electric cord or plug is
necessary, do not connect the equipment-
grounding conductor to a live terminal.
Check with a qualified electrician or service
personnel if the grounding instructions are not
completely understood, or if in doubt as to whether
the tool is properly grounded.
Repair or replace damaged or worn cord
immediately.
7.2 Extension Cords
If an extension cord is necessary, make sure the
cord rating is suitable for the amperage listed on
the trolley’s motor plate. An undersize cord will
cause a drop in line voltage resulting in loss of
power and overheating.
The chart in Table 3 shows the correct size cord to
use based on cord length and motor plate amp
rating. If in doubt, use the next heavier gauge. The
smaller the gauge number, the heavier the cord.
Recommended Gauges (AWG) of Extension Cords
Amps
Extension Cord Length *
25
feet
50
feet
75
feet
100
feet 150
feet 200
feet
< 5 16 16 16 14 12 12
5 to 8 16 16 14 12 10 NR
8 to 12 14 14 12 10 NR NR
12 to 15 12 12 10 10 NR NR
15 to 20 10 10 10 NR NR NR
21 to 30 10 NR NR NR NR NR
*based on limiting the line voltage drop to 5V at 150% of the
rated amperes.
NR: Not Recommended.
Table 3
7.3 Inspecting trolley motion
1. Before closing the circuit breaker and testing
the trolley, check that wiring has been
complete. If the trolley cannot be observed
when the circuit breaker is closed, station an
observer within sight of the trolley to report any
movement when power is applied to the trolley.
Be prepared to disconnect power if trolley
motor starts when the power is applied. The
trolley must remain motionless when power is
applied. Find and correct any problems before
continuing.
2. After all assembly and wiring is complete,
operate trolley forward and back a short
distance, then do likewise for the entire length
of the beam. Confirm that all adjustments and
operations are satisfactory.