Product data

23XL TYPICAL FIELD WIRING WITH OPTIONAL UNIT-MOUNTED STARTER (FRAME 1 AND 2 CHILLERS) (cont)
LEGEND
MCM — Thousand Circular Mils
NEMA — National Electrical Manufacturer’s Association
N.O. — Normally Open
PR — Pilot Relay
RLA — Rated Load Amps
ST — Shunt Trip
TB — Terminal Block
Required Power Wiring
Required Control Wiring
Options Wiring
NOTES:
I. GENERAL
1.0 Starters shall be designed and manufactured in accordance
with Carrier Engineering Requirement Z-375.
1.1 All field-supplied conductors, devices, field-installation wir-
ing, and termination of conductors and devices must be in
compliance with all applicable codes and job specifications.
1.2 The routing of field-installed conduit and conductors and the
location of field-installed, devices must not interfere with equip-
ment access or the reading, adjusting, or servicing of any
component.
1.3 Equipment installation and all starting and control devices
must comply with details in equipment submittal drawings
and literature.
1.4 Contacts and switches are shown in the position they would
assume with the circuit deenergized and the chiller shut down.
1.5 WARNING — Do not use aluminum conductors.
II. POWER WIRING TO STARTER
2.0 Power conductor rating must meet minimum unit nameplate
voltage and compressor motor RLA (rated load amps).
When (3) conductors are used:
Minimum ampacity per conductor = 1.25 x compressor RLA
When (6) conductors are used:
Minimum ampacity per conductor = 0.721 x compressor RLA
2.1 Lug adapters may be required if installation conditions dic-
tate that conductors be sized beyond the minimum ampacity
required. Solid-state starters are provided with:
A. Two (2) 0-250 MCM lugs provided per phase for power
conductor terminations when compressor motor RLA is
400 amps or less.
B. Three (3), 250-500 MCM lugs provided per phase for
power conductor terminations when compressor motor
RLA is more than 400 amps.
Wye-Delta starters are provided with:
A. Two (2) 250-500 MCM lugs provided per phase for power
conductor terminators when compressor motor RLA is
420 amps or less.
B. Two (2) #1-500 MCM lugs provided per phase for power
conductor terminations when compressor motor RLA is
more than 420 amps.
2.2 Power conductors to starter must enter through top of en-
closure. Flexible conduit should be used for the last few feet
to the enclosure to provide unit vibration isolation.
2.3 Compressor motor and controls must be grounded by using
equipment grounding lugs provided inside starter enclosure.
2.4 Wye-Delta starters require the assembly and the installation
of a ‘‘Top Hat’’ (located inside enclosure) to provide the re-
quired wire bending space for incoming power leads.
III. CONTROL WIRING
3.0 Field supplied control conductors to be at least 18 AWG
(American Wire Gage) or larger.
3.1 Chilled water and condenser water flow switch contacts, op-
tional remote start device contacts, and optional spare safety
device contacts must have 24 vdc rating. Max current is
60 mA, nominal current is 10 mA. Switches with gold plated
bifurcated contacts are recommended.
3.2 Remove jumper wire between 12A and 12B before connect-
ing auxiliary safeties between these terminals.
3.3 Pilot relays can control cooler and condenser pump and tower
fan motor contactor coil loads rated 10 amps at 115 vac up
to 3 amps at 600 vac. Control wiring required for Carrier to
start pumps and tower fan motors must be provided to as-
sure machine protection. If primary pump and tower fan mo-
tor control is by other means, also provide a parallel means
for control by Carrier. Do not use starter control transformer
as the power source for pilot relay loads.
3.4 Do not route control wiring carrying 30 v or less within a
conduit which has wires carrying 50 v or higher or along side
wires carrying 50 v or higher.
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