Nortek B5BM, Installation Instructions Manual

11

ELECTRICAL CONNECTIONS

 WARNING:

ELECTRICAL SHOCK, FIRE OR EXPLOSION 
HAZARD

Failure to follow safety warnings exactly could 
result in serious injury or property damage.

Improper servicing could result in dangerous 
operation, serious injury, death or property 
damage.

•  Before servicing, disconnect all electrical power 

to the air handler.

•  When servicing controls, label all wires prior 

to disconnecting. Reconnect wires correctly.

•  Verify proper operation after servicing.

•  Electrical  connections  must  be  in  compliance  with 

all applicable local codes and ordinances, and with 
the current revision of the National Electric Code 

(ANSI/NFPA 70).

•  For Canadian installations, the electrical connections 

and grounding shall comply with the current Canadian 
Electrical Code (CSA C22.1 and/or local codes).

Pre-Electrical Checklist:

√

 Verify the voltage, frequency, and phase of the supply 

source match the specifications on the unit rating plate.

√

  Verify that the service provided by the utility is sufficient 

to handle the additional load imposed by this equipment. 
See the unit wiring label or Table 3 (page 26) for proper 
high and low voltage wiring.

√

  Verify factory wiring is in accordance with the unit wiring 

diagram (Figures 14 - 19, pages 20 - 25). Verify none of 
the connections loosened during shipping or installation.

Line Voltage

• 

An electrical disconnect must be located within sight 
of and readily accessible to the unit. This switch shall 
be capable of electrically de-energizing the outdoor unit. 
See unit data label for proper incoming field wiring. Any 
other wiring methods must be acceptable to authority 
having jurisdiction.

•  It is recommended that the line voltage to the unit be 

supplied from a dedicated branch circuit containing the 
correct fuse or circuit breaker for the unit.

•  Overcurrent protection must be provided at the branch 

circuit distribution panel and sized as shown on the unit 
rating label and according to applicable local codes. See 
the unit rating plate and Table 3 (page 26) for maximum 
circuit ampacity and maximum overcurrent protection 
limits.

•  The  installer  should  become  familiar  with  the  wiring 

diagram/schematic before making any electrical 
connections to the unit.

•  Use only copper wire for the line voltage power supply 

to this unit. Use proper code agency listed conduit and 
a conduit connector for connecting the supply wires to 
the unit. Aluminum supply wire may be used if a heater 
kit is installed.

•  If replacing any of the original wires supplied with the 

unit, the replacement wire must be copper wire consisting 
of the same gauge and temperature rating.

•  Provide power supply for the unit in accordance with the 

unit wiring diagram, and the unit rating plate. Use UL 
listed conduit and conduit connectors for connecting the 
supply wires to the unit and for proper grounding. Field 
supplied bushings for the power supply cables must be 
added to support and protect the power supply cables. 

•  All 208/230 Volt units are shipped from the factory wired 

for 240 volt operation. For 208V operation, remove the 
lead from the transformer terminal marked 240V and 
connect it to the terminal marked 208V.

Grounding

 WARNING:

The unit cabinet must have an uninterrupted 
or unbroken electrical ground to minimize 
personal injury if an electrical fault should occur. 
Do not use gas piping as an electrical ground!

This unit must be electrically grounded in accordance 
with local codes or, in the absence of local codes, with 
the National Electrical Code (ANSI/NFPA 70) or the CSA 
C22.1 Electrical Code. Use the grounding lug provided in 
the control box for grounding the unit.

Thermostat / Low Voltage Connections

•  Thermostat connections shall be in accordance with the 

instructions supplied with the thermostat and the indoor 
equipment. The low voltage wires must be properly 
connected to the units low voltage terminal block.

•  A single stage thermostat is used with this equipment 

and must operate in conjunction with any installed 
accessories. Typical AC and air handler hookups are 
shown in Figure 12 (page 18).

 CAUTION:

Isolation must be maintained from the external 
Class 2 output of any transformer in a cooling 
circuit. Use a thermostat with isolating contacts 
to prevent inter-connection of Class 2 outputs.

•  Where local codes require that the thermostat wiring 

must be routed through a conduit or raceway, splices 
can be made inside the unit; however, all wiring must 
be NEC Class 1 and must be separated from incoming 
power leads.

•  The thermostat should be mounted about 5 feet above 

the floor on an inside wall. DO NOT install the thermostat