IM 1131-2 35
Electrical Data
Electrical Data
Electrical Notes
Notes for "Electrical Data Single Point" Power:
1 If a separate 115V power supply is used for the control
circuit, then the wire sizing amps is 10 amps for all unit
sizes.
2 Recommended power lead wire sizes for 3 conductors
per conduit are based on 100% conductor ampacity in
accordance with NEC. Voltage drop has not been
included. It is recommended that power leads be kept
short. All terminal block connections must be made with
copper (type THW) wire.
3 The recommended power lead wire sizes are based on an
ambient temperature of 86°F (30°C). Ampacity
correction factors must be applied for other ambient
temperatures. Refer to the National Electrical Code
Handbook.
4 Must be electrically grounded according to national and
local electrical codes.
Voltage Limitations:
1 Within 10 percent of nameplate rating
2 Voltage unbalance not to exceed 2% with a resultant
current unbalance of 6 to 10 times the voltage unbalance
per NEMA MG-1, 1998 Standard. This is an important
restriction that must be adhered to.
Notes for "Field Wiring Data"
1 Requires a single disconnect to supply electrical power
to the unit. This power supply must either be fused or use
an HACR type circuit breaker.
2 All field wiring to unit power block or optional non-
fused disconnect switch must be copper.
3 All field wire size values given in table apply to 75°C
rated wire per NEC.
Supplemental Overloads Option
The supplemental overloads option is used to reduce the
required electrical service size and wire sizing (cost) to the
water cooled version of WGZ chillers. The overloads reduce
the electrical requirements for the chiller because water-cooled
duty requires less power than air-cooled duty. The overload
option is only available for WGZ-DW models with water-
cooled condensers, having single point electrical power
connections, and can only be used if the condenser leaving
water temperature is 105°F or less. Refer to the Compressor
Amp Draw tables in the following electrical data for the
reduced electrical requirements.
Circuit Breakers
The circuit breaker used in the High Short Circuit panel option
may have a higher trip rating than the unit Maximum Overload
Protection (MOP) value shown on the unit name plate. The
circuit breaker is installed as a service disconnect switch and
does not function as branch circuit protection, mainly that the
protection device must be installed at the point of origin of the
power wiring. The breaker (disconnect switch) is oversized to
avoid nuisance trips at high ambient temperature conditions.
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