Having trouble with the back wire on GFCI's popping free. 20amp, 12 gauge wire. When I fold the wires into the box, they like to come free of the back wire hole. I suspect this is due to the difficulty bending the 20 gauge wire to fit into the box.
I've read this which suggests I should be using the back wire on the GFCI. A few other web sources say the same thing.
Earlier, I had a problem with just being at the conductor fill limit of what could fit inside the outlet box because I was using two GFCI outlets. I was unhappy with this and am rewiring so each box has one GFI and one normal 20amp outlet downstream. The GFCI is pigtailed. The regular outlet is side wired to the GFCI outlet so it protects the standard outlet.
I feel like I should side wire the GFI outlets because they keep popping out from the back wire, BUT numerous sources say that GFCIs should use the back wire. This is a proper back wire that gets screwed down, not the "Quick Wire" push in wiring. I'm hand tightening as much as I'm able.
I suspect it's the process of folding the wires into the box, with the 12 gauge being so stiff, that causes the wires to come loose. However, on the outlets I've done so far, I was able to eventually make it work. But in one case, I was getting an error with the GFCI tester, and it was because the neutral wire had popped out. I fixed it, but concerned over the long term if they might work their way out.