48 McQuay IM 987
Electrical Installation
Electrical Installation
Field Power Wiring
All of the unit side panels are hinged. Do not mount disconnect
switches and/or motor starters on panels that provide access to
internal components. Wiring conduits can penetrate the cabinet
bottom, base frame, or through the hinge and latch cap without
interfering with the access panels.
Note: Seal all holes cut into the unit to prevent water leakage.
Seal conduits connecting the unit to external panels, which
will be exposed to relative humidity and air pressure
differentials. Ground the motor using copper or other corrosion
resistant conductor.
Figure 55: Field Power Wiring
Wiring must comply with all applicable codes and ordinances.
The warranty is voided if wiring is not in accordance with
these specifications. An open fuse, tripped circuit breaker, or
Manual Motor Protector (MMP) indicates a short, ground, or
overload. Before replacing a fuse, circuit breaker, MMP, or
restarting a fan motor, identify the trouble and correct.
According to the National Electrical Code, a disconnecting
means shall be located within sight of and readily accessible
from the air conditioning equipment. The unit can be ordered
with an optional factory mounted disconnect switch. This
switch is not fused. Power leads must be over-current
protected at the point of distribution. The maximum rated
overcurrent protection device (MROPD) appears on the unit
nameplate.
All RDS and RAH Units
All units are provided with internal power wiring for single or
dual point power connection. The power block or an optional
disconnect switch is located within the main control panel.
Field power leads are brought into the unit through 3"
knockouts in the bottom of the main control panel. Refer to the
unit nameplate to determine the number of power connections.
See Figure 56 and Table 12, page 50.
If the unit has a factory mounted disconnect switch, generally
the switch must be turned off to open the main control panel
door. However, the door can be opened without disconnecting
power by following the procedure covered on page 126. If this
is done, use caution since power is not removed from the unit
or the controller.
Note: To wire entry points, refer to certified drawings for
dimensions.
Figure 56: RDS and RAH Power Wiring Connections
Hinge and
Latch Cap
Access
Panels
Top
Bottom
Must Seal
Access
Panel
Bottom
Base
Frame
WARNING
Hazardous voltage. Can cause severe injury or death.
Disconnect electric power before servicing equipment. More
than one disconnect may be required to de-energize the unit.
Electric heat
control panel
Optional
disconnect
(DS3)
3" power
knockouts
Optional
disconnect (DS2)
3" power
knockouts
Main disconnect (DS1)
or power block (PB1)
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