I saw some awesome conversation on this site that is very similar to my dilemma. Unfortunately, I have not found the root cause of my problem. Trying to wire in a GFCI outlet in bathroom. 6 wires. Identified the line and load circuits. When trip C/B in sub panel, I also lose power to 2 bedrooms, the switch in bathroom for lights, and the overhead fluorescent light in kitchen. Wall in bath is shared with kitchen. Hook up GFCI with just the line wires and GFCI works as it should. Hook up the load wires and nothing, outlet trips when hitting RESET. After finding this site with StingyB's similar problem, I did some investigation but don't have any GFCI's in those other rooms. Do I maybe have an outlet wired wrong in one of the other rooms?
Do you have spare space in your panel? There's a Code vio lurking here that we probably should fix...– ThreePhaseEelDec 23, 2018 at 5:28
That is a concern of mine. And no spare space in main or sub panels. All have CB's– TacoLoverDec 24, 2018 at 17:11
It sounds like you should post a new question about how to add room for more breakers to your setup, as what you're saying smacks of a serious space crisis...– ThreePhaseEelDec 24, 2018 at 17:14
Noting how you speak about Line and Load, it's clear that you have identified some of the wires as Line wires. Ok so far. However it appears that you are identifying all other wires as Load wires. that is not true. Granted, many GFCI instruction sheets mislead you in this area.
Actually all the wires are LINE wires, and all of them should be attached to the LINE terminals. The warning tape should be left on the LOAD terminals.
The only time you should attach to the Load terminals is when have identified a specific load that you actually want protected by GFCI, and where you have reasons for wanting to do that.
I am just now learning about how GFCI's work, and as you seem to understand, I have more to learn. The only outlet i'm worried about having GFCI is the one I'm trying to install in the bathroom to meet Code. I did not know these other rooms were wired to this outlet until now and they don't require GFCI protection as I understand it. I will try hooking it up with all wires going to LINE terminals. Dec 24, 2018 at 17:14
1This was it!!!!!! Thank you Harper!!!!!! Thanks for talking about it in simple terms. After thinking about your comment, it made sense to me. Hooked up all wires on LINE side and everything works like it should. And yes, the GFCI instruction sheet is misleading. Thanks again!!!! Dec 24, 2018 at 18:16
Yes, what you did will protect the sockets. It's possible to use the load terminals to protect downline loads, but it's wizard territory. When you try to apply it as you did to an existing circuit, often some tricky reorganizing needs to be done so they will load evenly and not trip the GFCI. That differs in every box so there's no way to give clear instructions on dealing with it. Dec 24, 2018 at 18:47
You could have an outlet wired wrong downstream from the GFCI. It would likely be a neutral-ground reversal, which a standard tester will not detect.
Other options are a fault in an appliance or fixed wiring - check everything for damage, and try it with everything unplugged.
You could also have a neutral going to another circuit, which is sometimes common with three way switching.
Consider splitting the circuit apart further down, to narrow down where the fault is.