I recently installed 2 ceiling fans with Lutron combination light and fan dimmer switches. On both circuits, if more than a half second or so is taken when selecting the fan speed (that is, a delay while between the low-medium-high states) the arc fault protection kicks in and shuts down the branch. There is no issue if I move fast enough between states or while the fan is in a steady state condition. This happens on two separate circuits with two identical fans and dimmers.
I'm going on the assumption that while the switch contactor is being moved there is either a small amount of arcing inside the switch or there is some EMI being generated that is offending the AFCI.
Should I go ahead and move to a non-AFCI breaker or are there any alternatives that I should consider?
Best Answer
Switches generate small, momentary arcs as part of their normal operation; AFCIs are designed to recognize and ignore these momentary arcs. However, holding the switch between positions (or taking a while to transition between positions) can lead to the arc sustaining itself, which damages the switch contacts and also causes the AFCI to trip because it sees an arc it doesn't recognize as harmless.
In other words: "Doctor, it hurts if I do this!" "Don't do that, then!"