My arc fault breaker won't reset. What should I do?

When an Arc-Fault Circuit Interrupter (AFCI) breaker refuses to reset and immediately trips back to the off position, it indicates that an active electrical fault, direct short circuit, or confirmed arc fault is still present on that branch circuit. To troubleshoot safely, first unplug every appliance, lamp, and electronic device connected to that circuit. Second, make sure to push the toggle handle all the way to the "Off" position to clear the internal mechanism before attempting to flip it back to "On". Third, inspect connected wiring for damage. You can troubleshoot electrical faults safely by shutting off power before inspection. You can verify that your corrective action is successful when unplugging faulty devices, clearing shorts, and flipping the AFCI breaker to "On" confirms that it holds a stable electrical load.