Can QO and HOM GFCI breakers work on circuits with VFDs and variable speed loads?

Issue:
Will QO and Homeline GFCI circuit breakers work on a load that generates high-frequency leakage current, such as a VFD, heat pump, mini-split, or EV charger, or will the high frequency cause the GFCI to nuisance trip?

Product Line:
Circuit Breakers: QO, QOB, Homeline

Resolution:
Standard QO and Homeline GFCI circuit breakers are evaluated at 60 Hz and trip between 4 mA and 6 mA. Variable-speed drives and power inverters shift leakage current well above 60 Hz, and HVAC systems commonly produce it between 5,000 Hz and 9,000 Hz. That leakage can push a standard GFCI past its threshold and cause tripping when no ground fault is present.

Square D HF-rated GFCI circuit breakers address this. They are certified under UL 943 and marked "Class A - HF" for use on circuits serving loads that produce high-frequency leakage current, including HVAC systems, heat pumps, mini-splits, EV chargers, pool and spa pumps, water pumps, and more. An HF-rated GFCI holds the same 4 mA to 6 mA Class A threshold at 60 Hz while allowing higher leakage at higher frequencies, so it can be used anywhere a standard Class A GFCI is used.

QO 2-pole HF-rated GFCI circuit breakers are plug-on neutral and available from 15 A to 60 A: QO215PGF (15 A), QO220PGF (20 A), QO225PGF (25 A), QO230PGF (30 A), QO235PGF (35 A), QO240PGF (40 A), QO245PGF (45 A), QO250PGF (50 A), and QO260PGF (60 A). HF-rated GFCI circuit breakers are currently available in the QO family, with Homeline versions planned for release.

Where an installed GFCI breaker trips on a variable-speed or inverter-driven load, replacing it with an HF-rated GFCI of the same amperage is the recommended step, and reduces return trips to the site.

For test data and the full technical background, see data bulletin 0760DB2501. For specifications, visit QO circuit breakers product page.

Released for: Schneider Electric Canada