5-565.1
9
electrical connections
1. Installation of wiring must conform with local building codes,
or in the absence of local codes, with the National Electric
Code ANSI/NFPA 70 - Latest Edition. Unit must be electri-
cally grounded in conformance to this code. In Canada,
wiring must comply with CSA C22.1, Part 1, Electrical Code.
2. Two copies of the job specific wiring diagram are provided
with each unit, one located in the duct furnace electrical
junction box and one in the electrical section of the unit.
Refer to this diagram for all wiring connections.
3. The wire gauge must be sized according to the National
Electric Code or CSA code based on the power supply
voltage, amp draw, and length of run. Refer to Table 9.1
for maximum wire lengths. Once the wire gauge has been
determined, refer to Table 9.2 for the number of wires for
which the low voltage terminal blocks in the unit are rated.
table 9.1 - low voltage (24v) maximum Wire length
(feet)
NEC-1996, Table 310-17, Copper wire with 90°C insulation,
conductors in free space (not in conduit), 86°F ambient. For
other wire types, refer to the NEC of CSA code.
table 9.2 - number of Wires Per terminal
4. Make sure all multi-voltage components (motors, transform-
ers, etc.) are wired in accordance with the power supply
voltage.
5. The power supply to the unit must be protected with a fused
or circuit breaker disconnect switch. Refer to the Factory
Mounted Option Locations (Figure 18.1) for the factory
mounted disconnect switch location and then review the
unit to determine if a factory installed dead front disconnect
switch was provided. Accessory field installed disconnect
switches should be mounted where shown in Figure 9.1. For
fusible disconnect switches, refer to the Model Identification
plate for the fuse size and type.
6. The power supply must be within 5% of the voltage rating
and each phase must be balanced within 2 percent of each
other. If not, advise the utility company.
7. External electrical service connections that must be installed
include:
a. Supply power connection (120, 208, 240, 480, or 600
volts).
b. Connection of thermostats, remote monitoring panels,
building pressure sensors, CO detectors, time clocks, or
any other accessory control devices that may be supplied
(24 volts).
8. Refer to the unit dimensional drawings on Figures 43.1
through 44.1 for the electrical knock-out locations.
9. All supply power electrical connections are made in the
electrical section of the unit. The low voltage (thermostat
and accessory control devices) can be wired to either the
electrical section or the duct furnace electrical junction box.
Refer to the wiring diagram for the terminal location of all low
voltage wiring.
cooling coil units
Models with a cooling section can be provided with either a
factory installed direct expansion (DX) evaporator, a chilled
fluid (for use with water, ethylene glycol, or propylene glycol
fluids) coil, or the coil can be field supplied and installed by
others. For units equipped with a factory installed cooling coil
(Digit 23 = 1), refer to the packing slip to determine the coil type
provided. The cooling section is located downstream of the
duct furnace heat exchanger in a blow-through configuration,
preventing condensation on the heat exchanger in the cooling
mode. Thus, a stainless steel heat exchanger is not required
when a cooling section is used. (However, a stainless steel heat
exchanger is still recommended when the combined entering/
return air to the unit is below 40°F.)
WARNING
1. Disconnect power supply before making wiring connections
to prevent electrical shock and equipment damage.
2. All appliances must be wired strictly in accordance with
wiring diagram furnished with the appliance. Any wiring
different from the wiring diagram could result in a hazard
to persons and property.
3. Any original factory wiring that requires replacement must
be replaced with wiring material having a temperature
rating of at least 105°C.
4. Ensure that the supply voltage to the appliance, as
indicated on the serial plate, is not 5% greater than rated
voltage.
Wire gauge
number of Wires per terminal
#10 AWG
1
#12 AWG
1 to 2
#14 AWG
1 to 3
#16 AWG
1 to 4
#18 AWG
1 to 5
#22 AWG
2 to 5
BLOWER
SECTION
DOOR
ELECTRICAL
SECTION
DOOR
DUCT
FURNACE
ELECTRIC SUPPLY
COMPONENTS MUST BE
CLEAR OF SERVICE DOORS
DISCONNECT
SWITCH WIRING,
AND CONNECTOR
figure 9.1 - recommended accessory field installed
disconnect switch mounting locations
model no. trans.
digit 15
va
18 ga
16ga
14 ga
12 ga
10 ga
1
40
162
216
315
360
495
2
75
86
115
168
192
264
3
150
43
58
84
96
132
4
250
26
35
50
58
79
Wire gauge
CAUTION
Ensure that the supply voltage to the appliance, as indicated
on the serial plate, is not 5% greater than rated voltage.
unit installation
unit installation
