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g/electrical • Posted by u/panel_pete •

GFCI breaker keeps tripping on a new construction — no fault found

New construction residential. AFCI/GFCI combo breaker (Square D HOM120CAFI) on a 20A kitchen circuit keeps tripping — not at load, just randomly. Sometimes in the middle of the night.

Ran a new circuit to verify it wasn't a wiring fault. Same issue. Swapped the breaker — same issue. Wiring is new 12/2 Romex, all connections are tight, no nicks in the insulation.

I'm running out of ideas. The GC thinks it's the refrigerator but the fridge is on its own dedicated circuit and that breaker doesn't trip. Any experience with nuisance trips on AFCI/GFCI combos in new construction?

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u/breaker_bob •

I've seen this with LED bulbs from cheap manufacturers. The switching supply in the driver creates an arcing signature. Switch to quality LEDs (Lutron, Cree, Philips) and the nuisance trips often stop. Also make sure any dimmers are rated for LED/CFL — old incandescent dimmers on LED circuits cause this constantly.

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u/nec_nerd •

AFCI combo breakers are notorious for nuisance trips with certain electronic loads. What's on the circuit? LED dimmers, smart switches, and some chargers emit high-frequency noise that the AFCI interprets as an arc signature. Try disconnecting every load and leaving the circuit energized overnight — if it doesn't trip, add loads back one at a time.

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u/admin_jake ADMIN •

Another thing: long neutral runs with high-resistance connections can confuse GFCI sensing. Even 2-3mA of leakage current is enough to trip. Check your neutral continuity end-to-end with a meter. New construction sometimes has neutral connections that aren't fully seated.

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