I never thought of an HACR breaker as having ground fault protection. I thought their specialty was performance in group motor applications as found in air conditioning equipment (motor-compressor plus outdoor fan in a condenser unit, for example).
Wouldn't 440.21 require a GFP type breaker tripping at 30mA, such as:
-- Cutler-Hammer "Ground Fault Equipment Protectors — 30 mA Sensitivity
QUICKLAG Type: QPGFEP 10,000 Ampere I.C. Thermal-Magnetic Breakers"
-- ...or SquareD "QO-EPD/EPE circuit breakers provide overload and short
circuit protection combined with Class B ground fault
protection. They are designed to provide ground fault
protection of equipment at a 30 milliampere level (EPD) or
100 milliamp level (EPE). They are not designed to protect
people from electrical shock."
I guess I can't say 30mA or 100mA is required, because the Art. 100 definitions of Ground-Fault Prot of Equip doesn't specify a certain fault level, just that it is "...less than those required to protect conductors from damage through the operation of a supply circuit overcurrent device."
kent