Arc-fault circuit breakers are a boon for household electrical safety. The garden-variety home electrical fire is usually started by the heat coming from a faulty wire arcing over. But as any radio enthusiast knows, sparks also give off broadband radio noise. Arc-fault circuit interrupters (AFCI) are special circuit breakers that listen for this noise in the power line and trip when they hear it. The problem is that they can be so sensitive that they cut out needlessly.

Our friend [Martin] moved into a new house, and discovered that he could flip the breakers by transmitting on the 20-meter band.

And of course, it’s a known problem in the Ham community. In particular, one manufacturer has had serious problems misinterpreting intentional radiation

RFI to Ground-Fault Circuit Interrupters
http://www.arrl.org/gfci-and-afci-devices

Ground-Fault Circuit Interrupters (GFCI) and Arc-Fault Circuit Interrupters (AFCI) circuit breakers are occasionally reported to “trip” (open the circuit) when a strong RF signal is present, usually a ham’s HF transmissions.

Under current codes, GFCI protection is required for all basement outlets, outdoor outlets, and for outlets in kitchens and bathrooms. AFCI protection is also required for all circuits that supply other specified rooms, such as bedrooms.

RF interference to GFCI breakers is caused by RF current or voltage upsetting normal operation of the imbalance detection circuit, resulting in the false detection of a fault. Similarly, RF current or voltage could upset the arc detection circuitry of an AFCI breaker.