23
Step 4 — Make Electrical Connections
GENERAL
—
Verify nameplate electrical requirements
match available power supply. Voltage at condenser must be
within the minimum and maximum shown in Tables 9 and 10.
Phases must be balanced within 2%. Contact local power com-
pany for line voltage corrections. Never operate a motor where
a phase imbalance in supply voltage is greater than 2%. Use
the following formula to determine the percentage of voltage
imbalance:
Example: Supply voltage is 240-3-60.
AB = 243 volts
BC = 236 volts
AC = 238 volts
Determine maximum deviation from average voltage:
(AB) 243 – 239 = 4 volts
(BC) 239 – 236 = 3 volts
(AC) 239 – 238 = 1 volt
Maximum deviation is then 4 volts. To determine the percent-
age of voltage imbalance:
This amount of phase imbalance is satisfactory since it is
below the maximum allowable of 2%.
Condenser operation on improper line voltage or excessive
phase imbalance may be considered abuse and any resulting
damage may not be covered by Carrier warranty.
All wiring must be in accordance with local or NEC
regulations.
POWER WIRING — All field power wiring must comply
with applicable local and national codes. Install field-supplied
branch circuit fused disconnect per NEC of a type that can be
locked OFF or OPEN. Disconnect must be within sight and
readily accessible from the unit in compliance with NEC Arti-
cle 440-14.
General Wiring Notes:
1. A terminal strip is provided for field-wired control
devices.
2. Power entry is at one end only.
3. All field power enters the unit through a hole located in
the corner post of the unit or the bottom of the control box
shelf. Refer to Fig. 19 for field power wiring details. Re-
fer to Fig. 5-9 for exact location of field power entry. See
Table 11 for incoming power wiring options.
4. Terminals for field power supply are suitable only for
copper conductors. Insulation must be rated 75 C
minimum.
5. Units with high short circuit ratings require that only
RK1, RK5, or J type fuses be used.
WARNING
Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.
IMPORTANT: When starting up this equipment for
operation, be sure to check tightness of all electrical ter-
minal connections, clamps, screws, etc., as they may
have become loose during shipment. It is also advisable
to re-tighten all electrical connections after equipment
has been in operation and components have reacted to
operating temperature.
IMPORTANT: Operating unit on improper supply
voltage or with excessive phase imbalance constitutes
abuse and may adversely affect Carrier warranty.
CAUTION
Proper rotation of condenser fan(s) MUST be verified.
Failure to comply could result in possible equipment
damage.
RELIEF
VALVE
*Field-supplied service valves.
Fig. 18 — Piping for Field-Supplied Receiver
A —
Bypass valve
B —
Receiver inlet valve
C —
Receiver outlet valve
a09-595
% Voltage
Imbalance = 100 x
max voltage deviation
from average voltage
Average voltage
Average Voltage =
243 + 236 + 238
3
=
717
3
= 239
% Voltage Imbalance = 100 x
4
239
= 1.7%
IMPORTANT: If supply voltage phase imbalance is
more than 2%, contact your local electric utility
company immediately.
