I do most of my own wiring in the shop and feel OK with what I do. But I have a weird problem in the outside outlets (original with house) that totally confuses me as to what is happening.
My main panel outside has two GFI circuits lableled "outdoor outlets". I do not exactly know which outlet is on which breaker, but we have outlets around the house, some in the overhang controlled by light sensors and a few scattered in the garden for Christmas lights (that's what the house blueprints say) and have an additional on/off switch indoors.
Outlet closest to panel is controlled by lower breaker, shows 125V between hot and neural (narrow plug, wide plug respectively), 125V between hot and ground, and 0.1 between neutral and ground. So far so good I think. Next outlet in the chain is the same. Third outlet in chain behaves weirdly. If I throw the lower GFI breaker, it reads 0V everywhere. Put the breaker back on and it show nearly 0v between hot and netural, 125V from ground to either hot or neutral. Sure looks like a short, but not bad enough to trip the breaker.
Now the strange part, if I throw the upper GFI breaker to off, then outlet three seems fine, voltages just like outlets 1 and 2. I asssume some other outlets somewhere will be completely off now, but I do not have a map of which outdoor outlets are on which breaker. Seems that the upper breaker (which apparently does not control these 3 outlets) somehow manages to interfere with some and not all the outlets on the adjacent breaker (hence I would assume it uses the other 120V branch).
The house was built in 1975 and the wiring is a nightmare, but I do not see how what I am observing is explained.