(
This annex is not part of the standard)
Annex A: Troubleshooting AFCIs, GFCIs, Fixed Wiring and
Appliances
AFCIs trip upon sensing arc-faults, and GFCIs trip upon sensing ground-faults. The circuit
breaker version of these devices also trip upon sensing overcurrent and short-circuits. In
addition to arc-faults, AFCIs can trip from high-voltage surges caused by lightning or utility
switching transients, voltage or frequency fluctuations form a poorly-regulated backup generator,
mechanical shocks such as earthquake, inadvertent grounding of the neutral conductor,
overcurrents, and short circuits.
When a protective device trips under load, the abnormal operating condition that caused the
device to operate should be investigated before placing the device back into service. The
following is a brief description of methods used to troubleshoot AFCIs, GFCIs, fixed wiring and
appliances to determine the most likely causes of the protective device operation.
A1. Troubleshooting
GFCIs
A defective GFCI may still provide power without providing ground-fault protection for
personnel. When a GFCI trips with an appliance plugged into the circuit, press the RESET
button once to reset the device. If the GFCI trips again, replace the GFCI. If the new GFCI trips
under similar conditions, the most likely cause is a ground-fault in the fixed branch circuit wiring
or in an appliance protected by the GFCI. Troubleshoot the fixed wiring and appliances
protected by the GFCI in accordance with Section A3.
A2. Troubleshooting
AFCIs
With the AFCI off, disconnect the branch circuit phase and neutral conductors from the AFCI.
Reset the AFCI. If the AFCI trips with no load conductors connected, replace the AFCI
immediately.
A2.1 New
Installations
Tripping of a newly installed AFCI is most often the result of improper wiring, installation or
application. Check for:
•
Multi-wire branch circuits, or phase conductors that share a neutral conductor.
•
Crossed or common neutral connections between branch circuits in a junction, outlet, or
switch box, or at the panel.
•
Neutral conductors inadvertently touching an exposed grounding conductor or terminal
on the load side of the AFCI.
•
Reversed neutral and grounding conductors.
