Greenheck Make-Up Air Electric, Steam, Hot Water, Chlled Water, and DX Coils (457046) - Manual (Page 3)

Electric Heater Option
General:
The requirements and practices described below are based on the National Electric Code and The Space Heating
Standard of the Underwriters Laboratories Inc. (UL). Although UL requirements are uniform throughout the
country, local electrical codes may deviate from the National Electrical Code; therefore, local inspection
authorities should be consulted regarding local requirements.
Electrical Wiring Instructions:
1. Use the wiring diagram supplied with the heater as a guide in correlating field wiring with the heater internal
wiring.
2. All field wiring to the heater must meet the requirements of the National Electric Code (NEC) and any other
applicable local or state codes.
3. Wiring to the heater must be rated for 75 o C minimum.
4. The fan is interlocked by the factory to the control circuit so the electric heater is not on unless the fan is
on.
5. If heater does not have a built-in disconnect switch or main circuit breaker, install a remote disconnect
(furnished by others) in accordance with the National Electric Code, Article 424-65.
Calculation of Line Currents:
(Amps) Single Phase Current =
Watts
Volts
Example: Single Phase 5 KW, 208 Volt
5000 Watts
= 24 Amps
208 Volts
Three Phase Current =
Watts
Volts x 1.73
Example: Three Phase 14.4 KW, 208 Volt
14400 Watts
=
14400
= 40 Amps
208 Volts x 1.73 360
3
WARNING: Electrical Shock Hazard! Disconnect all Power sources before doing
any work on the unit.
Sizing of Supply Conductors:
The required minimum size of supply conductors is marked at the field wiring terminals within the heater control
box; however, for reference the table on the following page is included. The wire gauges are calculated for 125%
of the heater line current as required by the National Electric Code, Article 424-3 (b) based on conductor
insulation rated for 75
o C (167 o F).