Reading 30 VAC?

[Copymutt]

Had a functional foyer light inside the garage double man door. Set up on an external photocell. It has always been intermittent.
Tried to add an exterior LED security to the same circuit. No light on either now. Traced the circuits and finding the common tie to the foyer light reads only 37 volts. Hot to ground same circuit is 120v. I suspect a loose wire nut in one of the junction boxes in the attic. Anyone have another thought?

 

[cmandp]

So you're getting 37v hot to neutral? Yeah, pretty sure you're only options there are bad neutral connection (wire nut, through fed outlet) somewhere along the way or a bad neutral wire (broken) somewhere along the way.

I'd check each hot leg to neutral at the panel too once you get back to there to check the circuits neutral connection on the neutral bar.

 

[Copymutt]

Found it! Thanks for the reply.

 

[cmandp]

That's good! Who wired that?

 

[wyliesdiesels]

wow

thats some sloppy work. i always twist wires before inserting into wire nuts. not required but helps to keep everything connected

doesnt look like the person whom did that even twisted their nuts which caused the wire to pull out. just inserted and stuffed 10lbs of **** in a 5lb box...

i would check every wire nut in that junction box. they all need twisting

 

[walta]

If your external photocell is the 2-wire variety it will not operate without a working old fashion incandesce lamp in the circuit.

If you want to go all LEDs you will need to upgrade the photocell the 3-wire variety.

Looks like at least one wire is not connected see photo.

Please draw a diagram of the circuit as wired and show us where you measured 37 volts







Walta

 

[Copymutt]

No diagram. At the inside ceiling incandescent light fixture has Switched hot wire and neutral (light connections).
Hot switched feeds wall switch then to exterior photo cell switch in series then to light. Neutral goes to the junction box pictured, the wire not seated. Additional downstream neutral also at the light read the same 30volts. All good w/ tightening the nut. Both sensors - ceiling and exterior security are 3 wire. After repairing the connection 119V hot to neutral at light, but still 30v hot to downstream neutral (b4 connecting). So that has to be a spurious reading.
Happy camper, good light now on the pad outside both man doors.

 

[bubinga]

That's good! Who wired that?

Looks a little full?

 

[walta]

If you are still actually reading 30 volts between ground and neutral that is a dangerous situation.

If the wiring is done correctly, it should not be possible to have 30 volts between ground and neutral. The other possibilities are a bad meter or misinterpreted meter readings.

Walta

 

[Copymutt]

Never had V between Neutral & ground.

 

[kngelv]

Look in the upper back right corner of the picture. You have a neutral tied to what looks like three hots in that gray wire nut.

James

 

[bubinga]

Look in the upper back right corner of the picture. You have a neutral tied to what looks like three hots in that gray wire nut.

James

Possible switch loop?

 

[TRWham]

And I see what looks like a red wire that goes nowhere.

 

[kngelv]

Possible switch loop?

Definitely possible. Would be nice to see some black tape on it if used this way.

James

 

[Copymutt]

The neutral tied to 3 hots has to be a switch circuit, not worried enough to confirm. The red wire is an unused conductor of a 4 wire 10 gauge 220 run to the garage sauna.

 

[engineer2]

I would shut all the power off to that box and twist those wires better using my Klein linesman pliers and then twist on the wire nuts.
If you are seeing 30V neutral to ground you likely have a shared neutral circuit.

 

[Meursault74]

reminds me of the time my brother asked me to change out an outdoor motion sensor light that wasn't working. I swapped it out and it still didn't work. I should have checked the voltage at the lamp first, but since those motion lights don't last too long I didn't. I then traced the lines. The "electrician" (I don't know who did it) that did the work for him had spliced the line into existing wiring nearby. The hot for that light was just put alongside the previously bundled/twisted wires and capped with a wire nut. It had loosened up because the splice was also in a box that had a pull cord lamp. Yeah, I undid all connections, twisted all the wires together at the same time with my pliers, then put on the wire nut and twisted some more, then used electrical tape on top of that. Doubtful it will loosen up again now.

Who would believe the wires weren't all twisted together. I see someone else is doing the same thing.

 

[Jehannum]

I've seen that before, in my house. I have aluminum branch wiring, which in and of itself isn't bad, but the work done after the fact by well intentioned idiots seems to always cause issues. The issue that caused the 30VAC on the neutral on my garage door, door bell, and furnace circuit was from my solar installers putting a subpanel in. They'd tied aluminum to copper without a purple nut, or twisting, or anything, and the neutral got so hot that it melted the insulation back and welded itself to a hot on my swamp cooler circuit inside my breaker box.

It was very bad juju, and damn near set my house on fire.

So, if you've got Copper to Aluminum joints somewhere in the line, I'd look at those first.

 

[justsam]

If you are going to re-dress that box, I would use Wago connectors, no twisting required. Also unless just not possible to do so, I would not leave the open part of the wire nut facing up, to collect any debris, condensation, etc. that the connection can stew in. Not an issue with Wago. Or since you seem to have found the problem, just fix the connection and move on!