440 – Air-Conditioning and Refrigerating Equipment

440.9 – Grounding and Bonding HACR Equipment

Change at a Glance:

Outdoor metallic raceway systems that use “compression-type fittings” required to contain a wire-type equipment grounding conductor when installed outdoors on a roof to supply HACR equipment.

440.9 Grounding and Bonding. (HACR Equipment)

Where multimotor and combination-load equipment is installed outdoors on a roof, an equipment grounding conductor of the wire type shall be installed in outdoor portions of metallic raceway systems that use non-threaded compression-type fittings.

440.32 – Branch-Circuit Conductors Supplying a Single Motor-Compressor

440.32 Single Motor-Compressor. (HACR Equipment)

Branch-circuit conductors supplying a single motor- compressor shall have an ampacity not less than the greater of:
(1) 125 percent of either the motor-compressor rated-load current
(2) 125 percent of the branch-circuit selection current, whichever is greater.
For a wye-start, delta-run connected motor-compressor, the selection of branch-circuit conductors between the controller and the motor-compressor shall be permitted to be based on 72 percent of either the motor-compressor rated-load current or the branch-circuit selection current, whichever is greater.
Informational Note: The individual motor circuit conductors of wye-start, delta-run connected motor- compressors carry 58 percent of the rated load current. The multiplier of 72 percent is obtained by multiplying 58 percent by 1.25.