I have an AFCI outlet in my foyer, and the circuit continues through that outlet and out to the porch for an overhead light above the front door, and then past that to the front of the house for an overhead lamp above the steps leading up to the porch. The two outside lights are on a switch inside the foyer, and the wiring runs through the porch roof. It's 'inside' in the sense that it's not exposed to the elements, but it's 'outdoors' in the sense that it's not inside the walls of my house, the construction is old, and there is some suspicion that the porch roof may have moisture in it.
When the circuit has load (i.e. one or both of the lights are installed), flipping the switch and supplying power will immediately trip the outlet. When there is no load (no lights are installed and the wires are not connected), flipping the switch does nothing.
It was suggested that the two possibilities are:
- The AFCI outlet is not rated for this use, and a small amount of moisture may be causing the trip
- The circuit has a short in it somewhere between the outlet and the first porch light. I've attached an image of how the porch light is wired. As you can see, the neutral on one of the wires does have a tiny nick, but it doesn't seem to go through to the copper.
What are people's thoughts about the most likely explanation?
Best Answer
The above are all excellent answers, but none was my actual problem. Because the wiring in this part of the house had a lot of stuff going on; it was installed with a floating neutral. I'm not sure if that's the correct term, but that's what it was called. Basically the neutral wire did not run back through the AFCI outlet, and instead when to the box via some other connection. This bypassed the AFCI outlet and resulted in it thinking there was a big fault and tripping immediately.