Mixed up Live and Neutral wires?

[celestia37]

Hello all, I'm new here

1) I have a newer home (so no old electrical) and yesterday I replaced the dining room ceiling fixture (put up pendant light). The wires on the fixture were initially labeled "L" (live) and "N" (neutral) on the very ends of them. Stupidly, because the wire was sooooooooo long, I cut off a bunch....but didn't pay any attention to which side of the wire (you split it off, one side of it is L and one side is N) was which. Yes, stupid me. So one side is connected to the BLACK (live) wire from the ceiling (and covered w/ wirenut) and the other side goes to WHITE (neutral).

I asked a friend what would happen if I mixed them up and the L went to the WHITE wire from the ceiling and the N went to the BLACK wire from the ceiling and he told me that if I didn't do it right, once the power was back on and I went to turn on the light, it just wouldn't work. IS THIS CORRECT - FOR SURE? My fear is that it still WOULD work, even though incorrectly paired up....but causing some kind of situaton where the incorrect wiring could cause too much heat up there and create a risk for fire. What do you think?

2) Could the Junction box ever fall down through the hole in the drywall? Now that I have the new fixture up and working, even though it's not very heavy, it does pull down a bit and there's a gap between the drywall and the trim plate thingy on the top of the fixture (that goes flush up against the drywall/ceiling). It's like the junction box (the silver metal thing) is a little loose. The round crossbar that's attached to it is secure, so that's not the problem...

The light stayed up all night (I was concerned the weight of the fixture might pull "something" down)....but that little gap up at the top bothers me. I'd rather not call an electrician if I don't have to, sort of defeats the purpose of doing this myself! But is that junction box pretty secure up in there or is there ever any risk that over time, the weight of the fixture could pull it down further and further until it comes right through the drywall?

Thanks so much !!

[LazyPup]

Most fixtures would have color coded wires with the black being the powered conductor, White is circuit common, and bare or green for grounding.

From you description it sounds like you have a hanging fixture that is wired with "Zip cord".

Zip cord is the molded two wire cord that we commonly associate with lamp cords or light duty extension cords. The wire is called zip cord because it can be cut at any point and the two wires separated like opening a zipper to make working leads to complete the wiring.

If you will examine the cord very carefully you will note that one of the two wires has a smooth covering while the other one has very small molded ribs running the full length of the wire. (Rub your finger nail across the wire and you can feel the ribs.)

The wire with the ribs is the "identified conductor" and it is supposed to be used as the circuit common or neutral, which is to be connected to the white wire from the source.

The wire with the smooth covering is the "non-identified conductor" and it is to be used as the circuit "power or line", and which is to be connected to the Black wire at the source.

When wiring a lamp socket the ribbed or "Identified conductor" is to be connected to the "Shell" The shell is the outer part of the lamp socket that has the screw threads to hold the light bulb.

The smooth wire (Non-identified conductor) is to be wired to the center contact of the light socket.

If you will examine a common lamp plug you will see that one of the two plug in tabs is wider than the other. The widest tab is the identified conductor and the ribbed wire should be attached to the wide tab.

Although a lamp will work with the wires connected either way, the intent here is to insure that only the center contact of the lamp holder is powered and the shell or outside part of the lamp holder is neutral.

If you happen to reverse the wires, the exterior part of the lampholder is powered and there is a potential that if someone were to touch it while touching another grounded surface they would get shocked.

[celestia37]

Yes, that's what I have, I guess..zip cord/wire. It's similar to stereo wire, where you split up the middle of it and each "side" of it contains wires ......one side goes to one thing, one goes to another.

However..I have an extra piece of it here in my hand...........I cannot see any differences in either "side"...the surface if it is smooth on both sides, totally. There is truly and absolutely no way to distinguish one side's wires from the other.

So now what do I do? I guess I have to call in an electrician and have him look?

[LazyPup]

If you happen to have a VOM (volt,ohm, milliameter) you could set it on "OHMS" then touch one test probe to the center contact in the light bulb socket and touch the bare ends of the wire with the other probe. The wire that shows continuity would be the "Line" wire and would go to the black conductor at the source.

[kactuskid]

Look at the wires again and see if there's any writing on either of the wires. The one that has writing on it is also the neutral wire. Otherwise, as lazypup mentioned, get yourself a multimeter and check for continuity to make sure which wire is which.
This diagram will show you the importance of having the wires connected correctly and how to check that they are.




As for your junction box, you should be able to see a screw or nail going through it that attaches it to a joist. If it's a metal box then you may be able to install another screw into the box and through the joist to secure it better. Or, if you have access to the attic then it would be wise to go up there and try to secure it better.

[HayZee518]

HERE ARE A FEW METAL BRACKET BOXES. THEY ALL FASTEN TO THE STRUCTURE TIMBERS.