DIY Home Improvement Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
450 Posts
Discussion Starter #1
Wife bought a new LED fixture fit the kitchen ceiling.

I have 3 white wires that were twisted together and one of the old light fixture wires went there, there are 2 black wires twisted together, and a single red wire that went to one of the light wires.

Untwisting all the wires, only one of the white wires has 116v power which my guess is feeding power to the other white wires, none of the black wires has power, the red wire has 30v when the wall switch is off, 116v when the wall switch is On. I have not checked anything else on this circuit but the circuit breaker box has only black wires on every breaker.the

Did someone connect the power white wire to a black hot somewhere prior to the ceiling light? If I track it down, I'm going to have to determine if one of the 2 black wires goes along with the hot white wire, then switch them? Hoping everything works?

Why does the red wire have 30v? Is this just an induction voltage feeding off a hot wire in the box?
 

Attachments

·
Registered
Joined
·
4,141 Posts
I untwisted the wires to determine which white wire was hot. But why is a white hot and a black not?
I'll make the assumption that cables are used in your wiring.
When creating a switch leg, unless you use a 3 wire cable you inevitably have a white wire that is powered rather than a neutral.
As long as the old fixture was working it was probably wired correctly. Wire it back the same way.
Receptacles have to observe polarity, white to white, black to black.
It's a different issue with switch legs.
As far as you voltage goes, it is most likely a phantom voltage.
Digital meters are fine but often misleading with line voltage where several wires are in the same junction box. An analog tester or even a non-contact tester would be more appropriate. I actually prefer a Wiggy.
 

·
retired framer
Joined
·
39,988 Posts
I'll make the assumption that cables are used in your wiring.
When creating a switch leg, unless you use a 3 wire cable you inevitably have a white wire that is powered rather than a neutral.
As long as the old fixture was working it was probably wired correctly. Wire it back the same way.
Receptacles have to observe polarity, white to white, black to black.
It's a different issue with switch legs.
As far as you voltage goes, it is most likely a phantom voltage.
Digital meters are fine but often misleading with line voltage where several wires are in the same junction box. An analog tester or even a non-contact tester would be more appropriate. I actually prefer a Wiggy.
Some thing else is turn on like a light so the tester is completing the circuit when checking that neutral. .
 

·
Registered
Joined
·
3,226 Posts
You should do some more book studying before working on electrical systems if you want to stay safe.

Any bunch of neutrals (white) wires will be carrying current if any load they run to is energized. If you disconnect those neutrals, you interrupt that current flow and the voltage being fed to the load will appear on that neutral. It can kill you just the same as if you touched the black wire of the same circuit!!! If you turned off the circuit breaker for the light you are working on and there is still voltage in that junction, you are working on what is called a Multi Wire Branch Circuit (aka MWBC). You need to turn off another breaker to completely de-energize that box for safe working conditions. If you don't, the neutral can become live under some circumstances when you disconnect them.

If you did not turn off a breaker but merely turned off the wall switch to work on that box, you have made a very dangerous decision and are risking your life needlessly. Experienced electricians rarely work on live junctions for good reason... it isn't necessary under hardly any circumstance. TURN OFF BREAKERS UNTIL THE BOX IS COMPLETELY DEAD... EVERY WIRE IN IT!!!

Once you get the box de-energized, twist the whites back together and nut your new fixture white to them. Connect your other fixture wire to the red. Attach the fixture to the box and turn the power back on for the final test. If the old fixture worked wired this same way, the new one will too.

I will add that there is something unusual about that particular combination of wire colors and neutrals so perhaps you can get a book on home electrical wiring basics and see how that could happen and what it means.
 

·
Registered
Joined
·
319 Posts
Without a clearer photo, I'll guess power comes into the switch, a 14-3 goes to the light with the red as switched (the OP said the red went to the light) and the black as constant power then then went onto other the other black/white pairs.
 

·
Registered
Joined
·
3,226 Posts
a 14-3 goes to the light with the red as switched (the OP said the red went to the light) and the black as constant power then then went onto other the other black/white pairs.
If you want to be a master electrician, you'll have to come up with a better solution than that. tip: There is only 2 blacks in the box and your solution would have 3.
 

·
Registered
Joined
·
319 Posts
If you want to be a master electrician, you'll have to come up with a better solution than that. tip: There is only 2 blacks in the box and your solution would have 3.

My bad. I thought I saw a 3rd in the bad photo. Re-reading the OP I see the comment on only 2 blacks. Thanks for the supportive comment.
 

·
Registered
Joined
·
450 Posts
Discussion Starter #11
The LED light works but there's a momentary delay when I turn the switch on. I'm hoping it's the nature of the LED fixture?

Should I re-check the wiring BECAUSE I may have put the fixture's white wire to the sole red wire and the fixture's black wire to the clump of white wires.
 

·
retired framer
Joined
·
39,988 Posts
The LED light works but there's a momentary delay when I turn the switch on. I'm hoping it's the nature of the LED fixture?

Should I re-check the wiring BECAUSE I may have put the fixture's white wire to the sole red wire and the fixture's black wire to the clump of white wires.
No, leave it, it's fine.
 

·
Registered
Joined
·
9,090 Posts
Nitpicking enough to give you a guilt trip.

Do not connect the light fixture's black lead to the white wire in the junction box.
Meanwhile he light fixture's white lead must be connected to white neutral.

Now, if it is working correctly and you do not measure voltage between exposed metal parts and nearby/not-so-nearby objects such as a heating radiator then you can leave it as-is for now.

If the only error is reversed white/nonwhite wire usage then that will not cause delayed or flickering light.
 

·
Registered
Joined
·
1,804 Posts
Why the hell did you do that?
That’s called “trying to learn electrical by disassembling your house”.

OP, just get yourself a book and spend an evening or two digesting it. The idea of trying to learn electrical with ad-hoc hit-and-miss knowledge (or God help you, the Internet) results in “swiss cheese” knowledge - you learn a few factoids but so much is left out. In particular, Google answers questions, and that doesn’t work if you don’t know what questions to ask.

For instance “which cables are legal in direct burial outdoors” is a question you’ll only ask if you realize NM-B *isn’t*.

Without a clearer photo, I'll guess power comes into the switch, a 14-3 goes to the light with the red as switched (the OP said the red went to the light) and the black as constant power then then went onto other the other black/white pairs.
Honestly, that’s my assessment too. I know surferdude2 doesn’t like it because OP says otherwise, but, hehe, I don’t believe OP :) That third white wire had to have come from somewhere... every cable with a white also has a black... conclusion: there’s a third black lurking out of sight. Perhaps it was disconnected and shoved in the back of the box for some reason.

——

So what’s going on?

My less flattering opinion conforms with jreagan: this box happens to be normally color coded, the /3 is hot-neutral-switchedhot going to the switch, and the other two B-W cables are just hot-neutral. One of those 3 is supply, the others carry always-hot to other points of use. When OP decided to part the neutrals (which I can forgive since the lamp neutral does need to be added to that bundle), OP cut the neutral connection for one of those downline loads. Current flows in loops, but not that current; it got stuck and backed up at OP’s break-of-neutral. Hence the 120V reading. The other leg didn’t happen to have any loads on it at the time.

OP #1 Now you know why they insulate neutrals. #2 this is why you don’t work with the power on! (Honestly how would it even enter your brain to do that).

——

My more flattering opinion is that things are *exactly* as OP said, there really are 2 blacks, and OP *did* turn off the breaker. That’s the same case as above, but with only one onward power instead of 2. The mystery white is a case of poaching. Another circuit elsewhere needed a neutral for some reason, so somebody either ran a cable with the black cut off, or just a loose white wire, and added it to this bundle. OP never knew to turn off this circuit (how would you??) but it was the same idea, that circuit had its neutral interrupted so current had nowhere to go. That would be a serious wiring defect that would need to be corrected PDQ.
 

·
Registered
Joined
·
3,226 Posts
I was hoping the OP would figure this out on his own and learn enough to help him stay safer working on electric wiring than he is now.

The way I see this, the electrician provided wiring for separate switching for a light and fan in the bathroom.

A home run comes to the box OP has opened and runs on through and down to the wall switch box. That takes care of the two nutted black wires that have no other connection.

Switched power comes back from the wall switch on the red of a 3-cond. cable. The neutral of that 3-cond. cable is unnecessarily nutted to the home run neutral (sets a parallel path). The black wire of the 3-cond. cable was intended to supply switched power for a fan. The fan wasn't installed so the black wire was either bobbed off or pushed back in the box and the OP didn't see it. Likewise it must be treated the same way in the wall switch box.

That seems like the only logical explanation that works for me. It means that the circuit breaker wasn't turned off when the OP disconnected the neutrals or else he wouldn't have drawn a spark. It also means that there is another energized load somewhere downstream on that neutral, like maybe another bathroom with a night light burning. If no second bathroom, then some other load... you can be sure there is another load that's energized.

The loop-tee- looped neutral should be corrected by removing it from the bundle and connecting it to the light only. It would make the hook up easier to understand and somewhat safer for anyone switching out a fixture next time. Paralleling that size wire is a code violation.
 
1 - 15 of 15 Posts
Top