11
Step 7 — Make Electrical Connections
FIELD POWER SUPPLY — All units except 208/230-v
units are factory wired for the voltage shown on the nameplate.
If the 208/230-v unit is to be connected to a 208-v power sup-
ply, the transformer must be rewired by moving the black wire
with the
1
/
4
-in. female space connector from the 230-volt con-
nection and moving to the 200-volt
1
/
4
-in. male terminal on the
primary side of the transformer.
Refer to unit label diagram for additional information. Pig-
tails are provided for field wire connections. Use factory-
supplied splices or UL (Underwriters’ Laboratories) approved
copper/aluminum connector.
When installing units, provide a disconnect per the NEC.
All field wiring must comply with NEC and local
requirements.
Install field wiring as follows:
1. Install conduit through side panel openings. Install con-
duit between disconnect and control box.
2. Install power lines to terminal connections as shown in
Fig. 9.
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate (see Tables 2A
and 2B). On 3-phase units, voltages between phases must be
balanced within 2% and the current within 10%. Use the formu-
la shown in the legend for Tables 2A and 2B, Note 2 to deter-
mine the percent of voltage imbalance. Operation on improper
line voltage or excessive phase imbalance constitutes abuse and
may cause damage to electrical components. Such operation
would invalidate any applicable Carrier warranty.
FIELD CONTROL WIRING — Install a Carrier-approved
accessory thermostat assembly according to installation
instructions included with the accessory. Locate thermostat
assembly on a solid wall in the conditioned space to sense aver-
age temperature in accordance with thermostat installation
instructions. Connect thermostat wires to terminal board.
Route thermostat cable or equivalent single leads of colored
wire from subbase terminals through connector on unit to low-
voltage connections (shown in Fig. 10).
NOTE: For wire runs up 50 ft, use no. 18 AWG (American
Wire Gage) insulated wire (35 C minimum). For 50 to 75 ft,
use no. 16 AWG insulated wire (35 C minimum). For over
75 ft, use no. 14 AWG insulated wire (35 C minimum). All
wire larger than no. 18 AWG cannot be directly connected to
the thermostat and will require a junction box and splice at the
thermostat.
Pass the control wires through the hole provided in the cor-
ner post; then feed wires through the raceway built into the
corner post to the 24-v barrier located on the left side of the
control box. See Fig. 11. The raceway provides the UL
required clearance between high- and low-voltage wiring.
HEAT ANTICIPATOR SETTINGS — Set heat anticipator
settings at .14 amp for the first stage and .14 amp for second-
stage heating, when available.
Unit cabinet must have an uninterrupted, unbroken electri-
cal ground to minimize the possibility of personal injury if
an electrical fault should occur. This ground may consist of
electrical wire connected to unit ground lug in control com-
partment, or conduit approved for electrical ground when
installed in accordance with NEC (National Electrical
Code), ANSI/NFPA, latest edition, and local electrical
codes. Do not use gas piping as an electrical ground. Fail-
ure to follow this warning could result in the installer being
liable for personal injury of others.
Fig. 7 — Flue Hood Details
LEGEND
NFGC —
National Fuel Gas Code
*Field supplied.
NOTE: Follow all local codes.
SPACING OF SUPPORTS
Fig. 8 — Gas Piping Guide (With Accessory
Thru-the-Curb Service Connections)
STEEL PIPE
NOMINAL DIAMETER
(in.)
X
DIMENSIONS
(feet)
1
/
2
6
3
/
4
or 1
8
1
1
/
4
or larger
10
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