11
12 ELECTRICAL AND CONTROL WIRING
IMPORTANT:
All routing of electrical wiring must be made
through provided electrical knockouts. When removing the
electircal knockouts, take care not to damage the PCB. 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 AIR HANDLER ON A THREE-
PHASE POWER SUPPLY. Measure the power supply to
the unit. The supply voltage
must
be measured and be
in agreement with the unit nameplate power requirements
and within the range shown.
12.2 Wire Sizing
Wire size is important to the operation of your equipment.
Use the following check list when selecting the appropri-
ate wire size for your unit.
•
Wire used must be sized to carry the Minimum
Circuit Ampacity (MCA) listed on the equipment’s
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 determining
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.
12.4 Electrical Connections – Supply Voltage
IMPORTANT NOTE: USE COPPER CONDUCTORS
ONLY.
Knockouts are provided on the air handler top panel
and sides of the cabinet to allow for the entry of the
supply voltage conductors, as shown in Figure 14. If the
knockouts on the cabinet sides are used for electrical
208-240
197
253
Nominal
Input
Minimum
Voltage
Maximum
Voltage
ELECTRICAL VOLTAGE
Table 7
HIGH VOLTAGE!
Disconnect ALL power before servicing or
installing this unit. 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. The 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.
FIRE HAZARD! To avoid the risk of property damage,
personal injury or fire, use only copper conductors.
CAUTION
Table 8
conduit, an adapter ring must be used in order to meet
UL1995 safety requirements. An NEC or CEC approved
strain relief is to be used at this entry point. Some codes/
municipalities require the supply wire to be enclosed in
conduit. Consult your local codes.
12.4.1 Air Handler Only (Non-Heat Kit Models)
The power supply connects to the stripped black and
red wires contained in the air handler electrical com-
partment. Attach the supply wires to the air handler
conductors as shown in the unit wiring diagram using
appropriately sized solderless connectors or other NEC
or CEC approved means. A ground lug is also provided
in the electrical compartment. The ground wire from the
power supply must be connected to this ground lug.
12.4.2 Air Handler - Non-Circuit Breaker Heat Kits
A terminal block is provided with the HKS kit to attach
the power supply and air handler connections. Follow
the HKS Installation Manual and wiring diagram for
complete wiring details.
12.4.3 Air Handler With Circuit Breaker Heat Kit
The air handler has a soft plastic cover on the upper
access panel and can be removed to allow the heater
kit circuit breaker to be installed. The circuit breakers
have lugs for power supply connection. See the HKS
Installation Instructions for further details.
