So I have four pairs of wires (4 black, 4 white)

If I hook up Black/White to Black/White one circuit is live
If I hook up the other Black/White to Black/White, I have anther circuit.

Then if I put all the four white wires together and all the black wires together, a third circuit starts working.

By circuit, I mean a light, outlet etc. How do two separate circuits, when combined, make a third work? I am very confused.

The problem is I am trying to install a new light fixture in a pre-existing location. The original fixture had all four white wires on one of the fixture screws and all the black wires on the other. I don't know how they got so many wires on the screws so I'm trying to make it so I dont need all four whites and all four blacks tied together on the fixture.

 

Any time you need to connect more than one wire to a screw, you need to use a wire nut to connect the multiple wires together with a "pigtail", a short segment of new wire. Then you connect the other end of the pigtail to the screw.

 

Although that doesn't answer my question, additional suggestions are always welcome. That suggestion is so good, it just might work. Thanks a bunch! I'm on it.

 

Exactly how are you testing? And how are you determining what a pair is? Can you physically see that they come from the same piece of cable?

If you really do have two circuits then you need to separate them. But I doubt that you really do.

 

Well one thing is for certain, all these wires are on the same circuit in the breaker box. If I turn the circuit off, nothing in the room works.

Now, there are eight wires. Each pair (black/white) can be identified as they come out of one bigger cable. There are four wires on one side of the box and four on the other.

If I take one specific black/white pair from the right, and connect it to a specific pair on the left, the ceiling light works.

If I do the same thing with the other four wires. Black/White from right to Black/white from left, then a set of wall outlets on the west side of the room start to work.

If all 4 white wires are connected and all 4 black wires are connected, the other wall outlets in the room begin working. In addition, this setup allows the light and outlets in one room over to start working.

It is all very odd.

White/Black White/Black
White/Black Box White/Black

I'm no electrician but I'm smart enough to know this doesn't make sense.

 

If the circuit is wired properly, one pair of wires should be hot. The other pairs should lead off to other receptacles or lights. Are you noticing that more than one pair of wires coming into the box is hot?

It would help if you used letters to identify the pairs of wires, such as A, B, C and D. In your other posts it is hard to follow.

 

It makes perfect sense.
You have one set of wires that brings power from the panel into the box. You 3 sets of wires that takes that power out to three other sections of the circuit. I see not problem at all with what you have.

 

Joe, that is my supposition also. However, his original post seems to imply that he can get incoming power on two pairs of wires. However, he then seems to contradict that later on.

 

You had me convinced for a second until I remembered it appears I have two pair of hot wires.

*Ceiling Light works*
Black A attached to Black W
White B attached to White X

*West Wall Outlets Work*
Black C attached to Black Y
White D attached to White Z

*Everything Works (Other wall circuits and all wiring one room over)
Connect Black A, C, W, X, Y
Connect White B, X, D, Z

If Black A and Black B are the only hot wires, for example, then the second 'circuit' shouldn't function without A/B, yet they do.

If I remember correctly, no other combination works.

I think I'm just going to have to accept my confusion because it seems like there is no explanation other than I'm missing something.

 

hmmm...I have looked at this point with a grin......I have to ask...how are you testing the wires.......are you using a volt meter....just curious and rather than getting discouraged.....test each black wire...and see how many are hot for sure......to eliminate any issues...

I find it hard to believe you can put all blacks and all whites together and have it work without SOME kind of issues.....

Would like to know what you find out.....sounds interesting........

 

I'm testing only by seeing what works using lamps, the lights themselves etc.

The only equipment I have is....

A basic four-way voltage tester
And one of these


I might have a multimeter somewhere but I've never figured out how to use it properly.

 

I guess I'm confused about why you are confused. If you disconnect some wires, you can usually expect something to quit working.

 

lol....Love that post John......anyway...look...

The LAMP method makes it hard to really get to the bottom of something.

The point I say this is with a Volt meter you can test each black line to see if it is hot.......and not just ramdom changing...who knows if you do it and then are simply supplying a line with a hot or the same one...I know how those old wires can look after time....trust me...

A cheap 10.00 volt meter at Lowes or Home Depot ( sorry john..I dont work at either but they do have some cheap meters...lol ) would do you some good at getting to the bottom of it...

I will take a stab at the fact in old houses they tend to feed the light box and drop down to the receps and other things......what I want to make sure if you are not back feeding a circuit and causing issues.....

Get a volt meter....they are easy..place it on AC and make sure you have it set to AC....just to be safe..lol....would hate to hear you smoked a DC one....

OK....I venture to say you have a single hot...and it has feeds from it....now I cant explain what you are saying except like john says...but It would help to know what you have in the box in the way of TRUE tested HOT lines...and not the lamp thing...for all you know the one you test is feeding one side of the house...and the other is feeding the other...and this is why they HOP....but we really need to know how many TRUE hots you have in the box without question.......a volt meter is GREAT to have my friend.


ALSO....I have to ask...did the light you are working in have a switch to it before.......big question because in old houses it would answer alot....and explain a few things...so enlighten me.....was it switched before?

 

Well Duh. I know I sound stupid right now, but I assure you I'm not.

Here's the way I see it. I connect two pairs of wires and the lights work. I connect the other two pair of wires, and 3 wall outlets work. I combine all four pairs and a third 'circuit' or whatever you want to call it magically starts working. This doesn't make sense because I haven't added anything the equitation.

I'm starting to wonder if perhaps I have one hot connection, but somewhere behind the wall, it's connected to another pair of wires (giving the illusion of two hot pairs). All these wires end up in the electrical box for some reason. That could explain things I suppose.

I will definitely check to see if I can identify hot wires with my equipment this evening after work and report back.

Electrical Man - The ceiling light has a switch. No surprise there. The light I am working on is in a walk-in closet and operates via a pull cord. Thanks.

I do appreciate everyone's comments. Thanks.

 

no it is not a surprise but I have seen EVERYTHING done before......and in old houses trust me CODE was the last thing they concerned themselves when wiring them.

I would venture to say you have a hot and it goes on 2 of those wires down to the switch on one and back on the other and so on and a neutral...but heck..what do I know.....lol......Good Luck !

I also figured you were talking about a light in a room itself..not a closet...my bad.......sorry....

Get a volt meter.....test them all...and find out WHICH are truly hot....

I have to ask.....how were they connected when you went INTO the box to begin with?

 

That sounds very reasonable. I'll see if I can check for that as well. Again, thanks guys. As a tech guy, I know how hard it is to diagnose problems without being able to see/touch.

 

The original fixture had all four white wires on one of the fixture screws and all the black wires on the other. I don't know how they got so many wires on the screws.

I bought a couple large wire nuts for the 5 14-guage wires at lunch, a per John Nelson, but hopefully I find a better solution tonight.

 

If that is the case......then you are fine....just use a wirenut for all the black and add a pig tail to supply the light fixture again and do the same for the whites....sounds to me again like a simply supply to the light and then dropping to feed the other circuits.......

Suggestion would be to just put it back the way it was unless you get the meter to check it....but if it was installed that way then that is what it is...simply a junction.......do the wirenut deal with a pigtail to your light and you are fine.

 

How many breakers does it take to kill all the circuits in the box?

 

It only takes one breaker. Anyway, I didnt have a lot of time last night to figure the darn thing out. I opted to just use the wire nuts and put it all together. That was a great idea from John. Thanks everyone!! This forum is helpful, I think I'll stick around.

 

Then it sounds like you have a looped circuit that comes back onto itself somehow.