Problem BC, residential.

[donf]

Greetings,

My Niece has a problem with a branch circuit that is intermittently cutting out and dropping circuits in two bedrooms.

The branch circuit, originates at position 14 on the panel. It is a 20 amp circuit.

I tested the output of the breaker at the panelboard and it was reading 120 VAC.

The home run goes from the panelboard to the first of two lights in the upstairs hallway. At the second light, the circuit splits and feeds several circuits in the master bedroom and all of the circuits in the 2nd. bedroom.

Both lights in the hallway are on. Apparently they wired from the first light to the second light using 12/3. At the second light, the red conductor feed the bulb on the second light.

The black conductor then connects to a bundle of blacks, which at this point I am guessing is the junction for the other two bedrooms.

There is 120 VAC between the neutral at the second light and the bundle of black conductors.

Neither of the bedrooms show any voltage. The first device in the circuit in the second bedroom is a fan/light. The switch loop to and from the light circuit has been verified using an Ohm meter.

There is no voltage present in any of the rooms outlets.

The original failure was that at intermittent times, the circuit would just drop dead and both bedrooms would lose power for several hours and then the circuit would just reactivate.

I checked the entire circuit for loose Neutrals, but I did not find any.

I'm open for more suggestions, please.

 

[ActionDave]

Both lights in the hallway are on. Apparently they wired from the first light to the second light using 12/3. At the second light, the red conductor feed the bulb on the second light.

The black conductor then connects to a bundle of blacks, which at this point I am guessing is the junction for the other two bedrooms.

Neither of the bedrooms show any voltage. The first device in the circuit in the second bedroom is a fan/light. The switch loop to and from the light circuit has been verified using an Ohm meter.

Lord have mercy I have trouble with more than four lines on a computer screen. My fault not yours.

It sounds like the red is a switch leg and the black is a constant hot. That would mean the problem is in the bundle of blacks in the first box or the fan/light in the bed room and the problem is only showing up when the circuit is loaded.

How many wires are under one wire nut in that bundle of blacks?

 

[donf]

Additional Information

Additional Information

Update:

At 2:00 AM this morning the lights and receptacles in the two bedrooms energized again.

I'm fairly certain now that the problem is not heat related, but caused by the first light in the circuit as you suggest. However, now I'm chasing a failure on a working circuit.

To answer your question, there are the two black conductors from the 2nd. light in the hall to the lamp. (Switched leg). The black leg of the 12/3 goes into a bundle of four blacks. I'm going to meter ot the parings and see if I isolate the pairing will it lead to a failure.

Hey, helper, bring me a Jamison's on the rocks and make it a triple!

 

[growler]

I checked the entire circuit for loose Neutrals, but I did not find any.

I'm open for more suggestions, please.

If you don't have any voltage in the bedrooms then a neutral is not the problem.

Check for voltage useing a voltage sensor and not a meter because this will not need a neutral to let you know it's still hot.

If you know that you have a break in the hot conductor then hook a signal tracer into the circuit (hot side) in the bedroom and follow it back toward the source.

If this is an old house there may be boxes in places that can't be seen or even flying splices in the ceiling or wall.

It's possible to find breaks in wires in odd places.

 

[CONDUIT]

Sounds like a typical loose connection on a stab in type receptacle. If the receptacles are the stab in type I would check for a loose connection. I have seen this time and time again over the years.

 

[readydave8]

sometimes the wire nut won't grab one conductor, circuit still works if its touching the others, probably twisted and may look good so you have to wiggle around, heat & cold & vibration & oxidation determine when circuit works and when not.

Or like the man says a backstab.

 

[donf]

Update:

Update:

DIY work, dirty words!

Okay, here's some more information:

Home run 14/2 AWG - 20 amp.

From light one to light 2, 14/3

12/2 AWG split into the bedrooms.

I'm picking up the new cable today.