Repeated loss power to lights but not receptacles without breaker tripping

Question

I'm having an issue with two recessed LED lights that are wired in-line. The power comes from a junction box (nothing else on this breaker has lost power, see below) down to a wall switch, back up to light #1 then on to light #2 (in the switch box the hot wires are attached to the switch and the white wires are attached together).

Three times now both LED lights have stopped working. Removing the LED units (these are he LED units that screw into a standard bulb receptacle in the can) and replacing with standard bulbs does not fix the problem and the LED units work within another system. I've changed out the switch twice and used a handheld tester to make sure power to traveling to the switch.

Twice now after fiddling with changing the switch and checking connections in the attic, the system suddenly begins to work again without an obvious change occurring. Typically the power will work normal for a day or two and then it stops again. Now after the third time, I have not tried fixing yet and the lights still do not work.

Nothing else on the same breaker is loosing power (a washing machine and four receptacles). The breaker has never tripped. I don't think it is too much power for the break; never tripped and lower power LEDS and I don't really use the receptacles apart from charging a phone and an 18 volt Dewalt drill battery. The wires are all new, I recently added the system when renovating a laundry room.

Any ideas what could be happening?

Answer 1

You appear to have an intermittent open circuit in one of the junctions (or the switch) affecting this circuit. Generally a bad connection, but it could be a bad switch, for the sake of completeness. But I guess you tried a different switch already, so, back to junctions.

This can be quite a problem, both because it's tedious to track down, and because it could result in an arc under just the right (or wrong, if you will) conditions - which could cause a fire.

There are many possible reasons for a connection to be intermittent and "fix itself" - changes in temperature can do it, or you may have several poor connections and as you check various places you move one of the problematic ones without solving its fundamental problem.

You should disassemble, check, and carefully reassemble every junction (both hot and neutral) that could cause the symptoms in the areas shown (so, not ones to other outlets, and not ones between fixtures, as both fixtures go out at the same time.) If your wire-nut skills are suspect, you might want to consider a listed push-in block connector - I don't personally like them, but I came to terms with the correct use of wire nuts some decades ago, and people who do use them claim they are not equivalent to back-stab connections and think they are easier for novices in wiring to use reliably.