Hello. A few days ago a single AFCI breaker was thrown and will not reset. I will note that there was no bad weather and no unusual loads on that line (room wasn't being used). Having said that - when I look at the breaker box, right by the switch in question I notice a clear plastic window. The ones that are still good are clear. The switch in question has yellow behind the window. So I am trying to get some ideas on what might be wrong. I do not plan on fixing this myself. :) Anyhow is it possible that the switch is bad? Or perhaps there is a short elsewhere? TIA! K

I'm talking a lot of greek here that I dont understand. Hopefully someone can help me out. The 3 power lines are 220v 8 gauge AL (black, red, & bare). There is one 8 gauge line going to the oven. There are two parallel wired, 8 gauge lines going to the range. All three lines are on one 40 amp breaker. The range came prewired with 12 gauge CU (red, black, white, & bare). I'm not sure of the wire type but it appears to have high temp insulation. The oven was prewired with 16 gauge CU (red, black, white, & bare). It also has the special insulation. The wires run through a flexible metal tubing pigtail (I don't know what it actual name of this tubing is). The old range was wired directly to the AL lines. The old oven had a pigtail and the connection to the AL lines were made in a metal terminal box. When I removed the old range and oven, the range showed no problems (i.e. overheating wires). The old oven on the other hand, showed some serious issues. The AL/CU connection in the terminal box were secured with wire nuts. The connection had overheated and one of the wire nuts had completely burned the insulation off. It's was just a matter of time until I had a fire or a direct short. After researching the AL/CU issue, I understand why the wiring had overheating. The problem I have now is, what do I do about it. I realize I could rewire the circuit but I want to avoid that if I can. I saw some information about information (http://tooling.tycoelectronics.com/copalum_home.stm) about adding Tyco COPALUM AL/CU pigtails. This seems like a reasonable option although I have not checked into the costs. Another solution seems to be a detailed wire nut installation (http://www.inspect-ny.com/aluminum/pl2p12.htm). Certainly the least expensive way to go. I also considered using an aluminum Thomas&Betts Splicer reducer ASR0214-B2 which are rated for a AL or CU connection. I would make my own pigtail and use shrink tubing to insulate the connection. I dont know if that is code or not. Anyway, I am looking for help on the AL/CU connection fix. As a side question, why would I need two AL parallel wired 8 gauge wires that terminates at a 12 gauge CU connection?