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12 Electrical and Control Wiring
IMPORTANT: All routing of electrical wiring must be made through provided electrical knockouts. Do not cut, puncture or
alter the cabinet for electrical wiring.
12.1 Building Electrical Service Inspection
This unit is designed for single-phase electrical supply only. DO NOT OPERATE ON A THREE-PHASE POWER
SUPPLY. Measure the power supply to the unit. The
supply voltage must be measured and be in agree-
ment with the unit nameplate power requirements and
within the range shown.
12.2 Wire Sizing
Wire size is important to the operation of your equip-
ment. Use the following check list when selecting the
appropriate wire size for your unit.
•
Wire used must carry the Minimum Circuit Ampac-
ity (MCA) listed on the unit's Series and Rating
Plate.
•
Refer to the NEC (USA) or CSA (Canada) for wire siz-
ing. The unit MCA for the air handler and the optional
electric heat kit can be found on the unit Series and
Rating Plate.
•
Wire must be sized to allow no more than a 2%
voltage drop from the building breaker/fuse panel
to the unit.
•
Wires with different insulation temperature rating have
varying ampacities - be sure to check the temperature
rating used.
Refer to the latest edition of the National Electric Code
or in Canada the Canadian Electric Code when deter-
mining the correct wire size.
12.3 Maximum Overcurrent Protection (MOP)
Every installation must include an NEC (USA) or CEC
(Canada) approved overcurrent protection device.
Also, check with local or state codes for any special
regional requirements.
Protection can be in the form of fusing or HACR style
circuit breakers. The Series and Rating Plate provides the maximum overcurrent device permissible.
NOTE: Fuses or circuit breakers are to be sized larger than the equipment MCA but not to exceed the MOP.
Nominal Input
Minimum Voltage
208-240
ELECTRICAL VOLTAGE
FIRE HAZARD!
To avoid the risk of property damage, personal injury
or fire, use only copper conductors.
HIGH VOLTAGE!
Disconnect ALL power before servicing.
Multiple power sources may be present.
Failure to do so may cause property damage,
personal injury or death.
HIGH VOLTAGE!
To avoid property damage, personal injury or death
due to electrical shock, this unit MUST have an
uninterrupted, unbroken
electrical ground circuit may consist of an
appropriately sized electrical wire connecting the
ground lug in the unit control box to the building
electrical service panel.
Other methods of grounding are permitted if performed
in accordance with the National Electric Code
(NEC)/American National Standards Institute
(ANSI)/National Fire Protection Association (NFPA) 70
and local/state codes. In Canada, electrical grounding
is to be in accordance with the Canadian Electric Code
(CSA) C22.1.
12
Maximum Voltage
197
253
Table 8
electrical ground. The
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