AFCI circuit protection trip from amateur radio transmission
AFCI protection comes in the form of circuit breakers, outlets, and dead-front outlets that protect downstream circuits from arc faults, which can lead to fires. Today’s AFCI protection is typically Combination AFCI with GFCI, which detects series or parallel arc faults and provides ground fault protection. AFCI are designed to detect and interrupt electrical arcs that can lead to fires, but they can sometimes be sensitive to the electromagnetic interference (EMI) generated by radio transmissions. Amateur radio and CB radio operators have reported instances where their radio transmissions cause AFCI (Arc Fault Circuit Interrupter) circuit protection to trip. Many early reported false trips were due to RF getting into the circuit and AFCI protection. As noted in the linked articles, a first solution may be replacing the AFCI with a newer model that has improved false-trip reduction.
AFCI can also be sensitive to current variation implicit in single-sideband (SSB) transmissions, which can cause the circuit breaker to trip if the rapidly varying current is interpreted as a series arc fault. We have observed that once the current draw on an AFCI circuit is above a certain threshold (say 5-10 amps), the AFCI becomes sensitive to the rapidly varying current draw of an SSB transmitter and falsely trips–even in the transmitter is only drawing say 1-2 amps at 120 volts. This can happen from having an electric heater or other high-current device on the same circuit as the radio, which can cause the AFCI to trip when the radio is transmitting at the same time the high-current device is drawing power. This can be verified by using a battery power supply for the transmitter, to help ensure it’s not coupled RF causing the issue. If the AFCI is new, the only solution may be to put the steady high-current loads and SSB transmitter on separate circuits. AFCI protection should not be removed, as it has proven effective in preventing fires.