12
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.
WARNING
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, PERSON-
AL INJURY OR DEATH.
WARNING
HIGH VOLTAGE!
TO AVOID PROPERTY DAMAGE, PERSONAL INJURY OR DEATH
DUE TO ELECTRICAL SHOCK, THIS UNIT MUST HAVE AN UNINTER-
RUPTED, 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 PER-
FORMED IN ACCORDANCE WITH THE NATIONAL ELECTRIC CODE
(NEC)/AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)/NA-
TIONAL 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.
12.1 Building Electrical Service Inspection
This unit is designed for single-phase electrical supply
only. DO NOT OPERATE ON A THREE-PHASE POW-
ER 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 equip-
ment. Use the following check list when selecting the
appropriate wire size for your unit.
• Wire used must carry the Minimum Circuit Ampacity
(MCA) listed on the unit’s Series and Rating Plate.
• Refer to the NEC (USA) or CSA (Canada) for wire
sizing. The unit MCA for the air handler and the op-
tional electric heat kit can be found on the unit Series
and Rating Plate.
• Wire must be sized to allow no more than a 2% volt-
age drop from the building breaker/fuse panel to the
unit.
•
Wires with different insulation temperature rating
have varying ampacities - be sure to check the tem-
perature 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.
