Carrier WeatherMaster 50HC14 Installation Instructions Manual page 16

ELECTRIC
DISCONNECT
SWITCH
Fig. 26 — Disconnect Switch and Unit
ALL UNITS
All field wiring must comply with NEC and all local re-
quirements.
Size wire based on MCA (Minimum Circuit Amps) on the
unit informative plate. See Fig. 25 and the unit label diagram
for power wiring connections to the unit power terminal
blocks and equipment ground. Refer to Table 3 for maximum
wire size at connection lugs.
Provide a ground-fault and short-circuit over-current pro-
tection device (fuse or breaker) per NEC Article 440 (or local
codes). Refer to unit informative data plate for MOCP (Maxi-
mum Over-current Protection) device size.
NOTE: Units ordered with factory installed HACR do not need
an additional ground-fault and short-circuit over-current protec-
tion device unless local codes require.
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 following formula to de-
termine the percent of voltage imbalance.
Example: Supply voltage is 230-3-60
A B C
MOTOR
(224 + 231 + 226)
Average Voltage =
Determine maximum deviation from average voltage.
(AB) 227-224 = 3 v
(BC) 231-227 = 4 v
(AC) 227-226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance = 100x
This amount of phase imbalance is satisfactory as it is below the max-
imum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more
than 2%, contact your local electric utility company immedi-
ately.
NOTE: Check all factory and field electrical connections for
tightness.
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 supply, the control transformer
must be rewired by moving the black wire with the
male spade connector from the 230-v connection and moving
it to the 200-v 1 / -in. male terminal on the primary side of the
4
COPPER
WIRE ONLY
ALUMINUM
WIRE
AB = 224 v
BC = 231 v
AC = 226 v
681
= =
3 3
4
= 1.78%
227
1 / -in. fe-
4
transformer. Refer to unit label diagram for additional
information.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage.
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.
NOTE: Check all factory and field electrical connections for
tightness.
UNITS WITHOUT FACTORY-INSTALLED NON-FUSED
DISCONNECT OR HACR
When installing units, provide a disconnect switch of ade-
quate size per NEC (National Electrical Code). Disconnect
sizing data is provided on the unit informative plate. Locate
on unit cabinet or within sight of the unit per national or local
codes. Do not cover unit informative plate if mounting the
disconnect on the unit cabinet.
UNITS WITH FACTORY-INSTALLED NON-FUSED DIS-
CONNECT OR HACR
The factory-installed option non-fused disconnect switch
(NFD) is located in a weatherproof enclosure located under
the main control box. The manual switch handle is shipped in
the disconnect or HACR enclosure. Assemble the shaft and
handle to the switch or HACR at this point. Discard the facto-
ry test leads (see Fig. 25). The factory disconnect is a 200A
disconnect on 230-3-60 units and a 100A disconnect on 460-
3-60 and 575-3-60 units. On units with factory installed non-
fused disconnect, without factory installed electric heat, the
factory supplied load side wires may be of insufficient size
for accessory electric heat applications. If so, remove the load
side factory wiring. Re-size wires per unit nameplate data
provided with accessory electric heat.
227
Fig. 27 — Location of Non-Fused Disconnect
To field-install the NFD shaft and handle:
16
CAUTION
Enclosure