39
Fig. 48 — NFD Handle and Shaft Assembly
(Sizes 07-14)
When installing units, provide a disconnect switch per NEC
(National Electrical Code) of adequate size. Disconnect sizing
data is provided on the unit informative plate. Locate discon-
nect sizing data 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.
FIELD WIRING FOR 50TC 07-14 UNITS
All field wiring must comply with NEC and all local codes. Size
wire based on MCA (Minimum Circuit Amps) on the unit infor-
mative plate. See Fig. 49 and the unit label diagram for power
wiring connections to the unit power terminal blocks and equip-
ment ground. Maximum wire size is #4 ga AWG per pole.
Fig. 49 — Power Wiring Connections (Sizes 07-14)
Provide a ground-fault and short-circuit over-current protection
device (fuse or breaker) per NEC Article 440 (or local codes).
Refer to unit informative data plate for MOCP (Maximum
Over-current Protection) device size.
All field wiring must comply with the NEC and local
requirements.
All units except 208/230-v units are factory wired for the volt-
age shown on the nameplate. If the 208/230-v unit is to be con-
nected to a 208-v power supply, the control transformer must
be rewired by moving the black wire with the
1
/
4
-in. female
spade connector from the 230-v connection and moving it to
the 200-v
1
/
4
-in. male terminal on the primary side of the trans-
former. Refer to unit label diagram for additional information.
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. 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:
Example: Supply voltage is 230-3-60
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.
This amount of phase imbalance is satisfactory as it is below the maxi-
mum allowable 2%.
NOTE: Check all factory and field electrical connections for tightness.
CONVENIENCE OUTLETS FOR 50TC 07-14 UNITS
Two types of convenience outlets are offered on 50TC models:
non-powered and unit-powered. Both types provide a 125-v
GFCI (ground-fault circuit-interrupter) duplex receptacle rated
at 15-A behind a hinged waterproof access cover, located on
the end panel of the unit. See Fig. 50.
C IFC
Disconnect factory test leads
and discard.
13 13
L1
L2 L3
208/230-3-60
460-3-60
575-3-60
Units Without Disconnect Option
Units With Disconnect Option
13 5
24 6
L1 L2 L3
Factory
Wiring
Disconnect
per
NEC
Optional
Disconnect
Switch
11
= 100 x
max voltage deviation from average voltage
average voltage
AB = 224 v
BC = 231 v
AC = 226 v
Average Voltage =
(224 + 231 + 226)
=
681
= 227
33
% Voltage Imbalance = 100x
4
= 1.78%
227
IMPORTANT: If the supply voltage phase imbalance is more than 2%,
contact your local electric utility company immediately.
WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal inju-
ry or death.
Units with convenience outlet circuits may use multiple
disconnects. Check convenience outlet for power status
before opening unit for service. Locate its disconnect
switch, if appropriate, and open it. Lock-out and tag-out
this switch, if necessary.
A
B
C
MOTOR
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