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Fig. 24 — Thru-Base Connection Fittings
Check tightness of connector lock nuts before connecting
electrical conduits.
Field-supplied and field-installed liquid-tight conduit con-
nectors and conduit may be attached to the connectors on the
basepan. Pull correctly rated high voltage and low voltage
through appropriate conduits. Connect the power conduit to the
internal disconnect (if unit is so equipped) or to the external
disconnect (through unit side panel). A hole must be field cut in
the main control box bottom on the left side so the 24-v control
connections can be made. Connect the control power conduit to
the unit control box at this hole.
UNITS WITHOUT THRU-BASE CONNECTIONS
1. Install power wiring conduit through side panel openings.
Install conduit between disconnect and control box.
2. Install power lines to terminal connections as shown in
Fig. 15.
Voltage to compressor terminals during operation must be
within voltage range indicated on unit nameplate. On 3-phase
units, voltages between phases must be balanced within 2%
and the current within 10%. Use the formula shown below to
determine the percent of voltage imbalance. Operation on im-
proper line voltage or excessive phase imbalance constitutes
abuse and may cause damage to electrical components. Such
operation would invalidate any applicable Carrier warranty.
% Voltage imbalance
max voltage deviation from average voltage
= 100 x
average voltage
Example: Supply voltage is 230-3-60.
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =
Determine maximum deviation from average voltage.
(AB) 227
224 = 3 v
–
227 = 4 v
(BC) 231
–
(AC) 227
226 = 1 v
–
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance= 100 x
= 1.76%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR
224 + 231 + 226
3
681
=
3
= 227
4
226
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.
FIELD CONTROL WIRING — The 50TC unit requires an
external temperature control device. This device can be a ther-
mostat (field-supplied) or a PremierLink™ controller (avail-
able as factory-installed option or as field-installed accessory,
for use on a Carrier Comfort Network
trol) or the RTU Open Controller for Building Management
Systems using non-CCN protocols (RTU Open is available as a
factory-installed option only).
THERMOSTAT — Select a Carrier-approved accessory
thermostat. When electric heat is installed in the 50TC unit, the
thermostat must be capable of energizing the G terminal (to
energize the Indoor Fan Contactor) whenever there is a space
call for heat (energizing the W1 terminal). The accessory ther-
mostats listed on the unit price pages can provide this signal
but they are not configured to enable this signal as shipped.
Install the accessory thermostat according to installation in-
structions included with the accessory.
Locate the thermostat accessory on a solid wall in the condi-
tioned space to sense average temperature in accordance with
the thermostat installation instructions.
If the thermostat contains a logic circuit requiring 24-v pow-
er, use a thermostat cable or equivalent single leads of different
colors with minimum of seven leads. If the thermostat does not
require a 24-v source (no "C" connection required), use a ther-
mostat cable or equivalent with minimum of six leads. Check
the thermostat installation instructions for additional features
which might require additional conductors in the cable.
For wire runs up to 50 ft. (15 m), use no. 18 AWG (Ameri-
can Wire Gage) insulated wire [35°C (95°F) minimum]. For 50
to 75 ft. (15 to 23 m), use no. 16 AWG insulated wire [35°C
(95°F) minimum]. For over 75 ft. (23 m), use no. 14 AWG in-
sulated wire [35°C (95°F) minimum]. All wire sizes larger than
no. 18 AWG cannot be directly connected to the thermostat and
will require a junction box and splice at the thermostat.
16
or as a stand alone con-
®
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