Product data

23XL TYPICAL FIELD WIRING WITH FREE-STANDING STARTER (FRAME 1 AND 2 CHILLERS) (cont)
LEGEND
LL — Compressor Motor Starter Terminals
MCM — Thousand Circular Mils
NEMA — National Electrical Manufacturer’s Association
NFPA — National Fire Protection Association
N.O. — Normally Open
PR — Pilot Relay
RLA — Rated Load Amps
T—Terminal
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.
1.6 Installer is responsible for any damage caused by improper
wiring between starter and machine.
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. Contact starter supplier for lug information.
2.2 Compressor motor and controls must be grounded by using
equipment grounding lugs provided inside starter enclosure.
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.
3.5 Voltage selector switch in machine power panel is factory
set for 115 v control power source. When 230 v control power
source is used, set switch to 230 v position.
3.6 Control wiring cables between starter and power panel must
be shielded with minimum rating of 600 v, 80 C. Ground shield
at starter.
3.7 For 23XL chillers with free-standing starters, voltage to ter-
minals LL1 and LL2 comes from a control transformer in a
starter built to Carrier specifications. Do not connect an out-
side source of control power to the compressor motor starter
terminals (LL1 and LL2). An outside power source will pro-
duce dangerous voltage at the line side of the starter, be-
cause supplying voltage at the transformer secondary ter-
minals produces input level voltage at the transformer primary
terminals.
IV. POWER WIRING BETWEEN STARTER AND COMPRESSOR
MOTOR
4.0 Low voltage (600 v or less) compressor motors have (6)
1
⁄ 2 in. terminal studs (lead connectors not supplied by
Carrier). Either 3 or 6 leads must be run between compres-
sor motor and starter, depending on type of motor starter
employed. If only 3 leads are required, jumper motor termi-
nals as follows: 1 to 6, 2 to 4, 3 to 5. Center to center dis-
tance between terminals is 2.73 inches. Compressor motor
starter must have nameplate stamped as conforming with
Carrier requirement ‘‘Z-375.’’
4.1 When more than one conduit is used to run conductors from
starter to compressor motor terminal box, one conductor from
each phase must be in each conduit, to prevent excessive
heating. (e.g., conductors to motor terminals 1, 2, and 3 in
one conduit, and those to 4, 5, and 6 in another.)
4.2 Compressor motor power connections can be made through
top, bottom, or right side of compressor motor terminal box
by rotating the terminal box and using holes cut by contrac-
tor to suit conduit. Flexible conduit should be used for the
last few feet to the terminal box for unit vibration isolation.
Use of stress cones or 12 conductors larger than 500 MCM
may require an oversize (special) motor terminal box (not
supplied by Carrier). Lead connections between 3-phase mo-
tors and their starters must not be insulated until Carrier per-
sonnel have checked compressor rotation.
4.3 Compressor motor frame to be grounded in accordance with
the National Electrical Code (NFPA-70) and applicable codes.
Means for grounding compressor motor is (2) Thomas and
Betts pressure connectors for 350 to 800 MCM wire, sup-
plied and located in the back upper and lower right side cor-
ners of the compressor motor terminal box.
4.4 Do not allow motor terminals to support weight of wire cables.
Use cable supports and strain reliefs as required.
4.5 Use back up wrench when tightening lead connectors to
motor terminal studs. Torque to 10-15 lb-ft max.
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