Table of Contents
Advertisement
Electrical Installation
All Units
The minimum circuit ampacity (wire sizing amps) is shown on
the unit nameplate. Refer to Table 23 on page 59 for the
recommended number of power wires.
Copper wire is required for all conductors. Size wires in
accordance with the ampacity tables in Article 310 of the
National Electrical Code. If long wires are required, it may be
necessary to increase the wire size to prevent excessive voltage
drop. Size wires for a maximum of 3% voltage drop. Supply
voltage must not vary by more than 10% of nameplate. Phase
voltage imbalance must not exceed 2%. (Calculate the average
voltage of the three legs. The leg with voltage deviating the
farthest from the average value must not be more than 2%
away.) Contact the local power company for correction of
improper voltage or phase imbalance.
Provide proper line voltage and phase balance.
Improper line voltage or excessive phase imbalance constitutes
product abuse. It can cause severe damage to the unit's
electrical components.
A ground lug is provided in the control panel for each
disconnect or power block. Size grounding conductor in
accordance with Table 250-122 of the National Electrical
Code.
In compliance with the National Electrical Code, an
electrically isolated 115V circuit is provided in the unit to
supply the factory mounted service receptacle outlet and
optional unit lights. This circuit is powered by a field
connected 15A, 115V power supply. Leads are brought in
through a 7/8" knockout in the bottom of the main control
panel, near the power wire entry point.
50
CAUTION
Table 11: Multiple Point Power Connection Options
Number of
Disconnect
electrical
designation
circuits
DS2
2
DS1
DS3
2
DS1
Table 12: Recommended 3-phase Power Wiring To Ensure
Disconnects and Power Blocks Mate with Power Wiring
Insulation
Wire
Qty./
rating
gauge
pole
(°C)
10
1
75
8
1
75
6
1
75
4
1
75
3
1
75
2
1
75
1
1
75
1/0
1
75
2/0
1
75
3/0
1
75
4/0
1
75
250
1
75
300
1
75
350
1
75
400
1
75
500
1
75
3/0
2
75
4/0
2
75
250
2
75
300
2
75
350
2
75
400
2
75
500
2
75
250
3
75
300
3
75
350
3
75
Note:
All wire sizes assume separate conduit for each set of parallel
conductors.
Note:
All wire sizes based on NEC Table 310-16 for 75°C THW wire
(copper). Canadian electrical code wire ampacities may vary.
Note:
All wire sizes assume no voltage drop for short power leads.
Location
Load
(see
Figure 2,
page
Supply and return fan
Main control panel
motors plus controls
Balance of unit
Main control panel
Electric heat
Electric heat
control panel
Balance of unit
Main control panel
For MCA
No. of
Conduit
conduits
(trade size, in.)
1
1/2
1
3/4
1
1
1
1 1/4
1
1 1/4
1
1 1/4
1
1 1/4
1
1 1/2
1
2
1
2
1
2
1
2 1/2
1
2 1/2
1
3
1
3
1
3
2
2
2
2
2
2 1/2
2
2 1/2
2
3
2
3
2
3
3
2 1/2
3
2 1/2
3
3
McQuay IM 987
4)
up to
(amps)
35
50
65
85
100
115
130
150
175
200
230
255
285
310
335
380
400
460
510
570
620
670
760
765
855
930
Hide quick links:
Advertisement
Table of Contents
