+1

I've replaced a bad breaker on my mother's house. Was driving me mad checking everything, and the breaker looked like it was open when it was closed.

How old is the house? I found that over the years, home owners or handy man specials may have done some creative electrical work? Is this a lighting circuit? If so come morning, shut off breakers and start opening j boxes and unscrew wire nuts. I bet the dumb ass electrical contractor did not use a pliers to twist the wires before he tie it up with wire nuts. Its pretty common that these guys will hold the two wires together and just twist on the wire nuts. now its loose causing a breaking in the connection. Just open the J box and start undoing wire nuts until you find the loose one. They might be be up in the attic, depending on the age of the house and if it was remodeled by some contractor with creative electrical work such as boxes buried behind drywall, cabinets, attics?

A few answers to some of the questions...

The house was built in the 70's, there is no aluminum wire, all copper. There is no evidence of poor wiring practices, there was a major reno done, but it was done properly.

The GFCI is a good point, I could be downstream of a tripped receptacle, but I am unaware of any that aren't functioning.

I do not have a bad breaker, I have checked the output of every breaker. I also do not have a bad neutral wire.

I do agree that I likely have a failed Marr connector twisted joint somewhere, anything else is far less likely.

I do not know which breaker is supposed to be feeding the dead circuit, in fact I don't even know which breaker box (I have two) should be feeding it. Judging by the age of the wires in the box I suspect it is from the original breaker box.

I have a 'chirp' sensor, but my wires are all dead. I could use that device to check any boxes I open, if I end up going that route.

Someone has loaned me a cheap tracer, I will try to find the problem this weekend. My experience has been that every wire in the house shows as being on the circuit. Perhaps I can isolate the black wire and work back to the breaker box.

That can be a hidden issue. Our house was built 25 years ago. It has GFI circuits and some electrician had a sense of humor or an evil streak. We plugged into an outside electrical socket to run a power tool. Somehow that popped a GFI breaker in the bathroom. It took me a while to figure that one out. The breaker was fine at the box, but the electrical outlet in the bathroom by the sink popped the GFI.

how are you checking power.
hot side to neutral AND to ground.
you can have a bad neutral connection.

When you execute the tracing - make sure your breakers are all off. I think you're likely to find a loose wire nut junction somewhere.

Exterior plugs needs to be GFI protected. Yes, he cheated .

Fluke meter to known ground and to neutral. There is no evidence that I have a failed neutral in addition to a failed power connection. But if that is the case it is a second issue.

I agree. Just not easy to find...

I was finally able to get into my attic and trace the wire.

Using a 'fox and hound' wire tracer, and knocking some holes in the garage drywall, I was able to fund a tripped GFI behind a paint cabinet.

Six months of screwing around for a faulty hidden GFI...

"hidden GFCI"

WTF? At least it's no longer hidden.

Lol.
Someone earlier in the thread had mentioned the possibility of a gfi hiding somewhere. Having seen that a few times before, I though that might just be it.
Good to finally solve a mystery without having to rip out too much drywall or running new wire.

Fun... I discovered that our garage door was also on a GFI circuit after a big storm. To make a long story short, I taped a big post it note on the inside of the fuse box to look for the GFI plug just 5 feet from the box, saying to reset it if the garage door doesn't work.
Definitely not as painful as your issue though.

I'll take credit :) Post #20.