Question about a circuit in a series

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  #1  
Old 06-06-15, 12:48 PM
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Question about a circuit in a series

I've temporarily pulled down a wall light fixture to have it revitalized. Apparently it's on the same circuit as my attic fan. It's been a few years since I hung out in this electrical forum and I'm having trouble finding my book. What can I do as a temporary fix? The fixture is going to be down a few days.

Thanks

ETA: It occurs to me that I could just wire another fixture or an outlet in place -- I have some laying around -- but having something just dangling there could get in the way of the wall painting.

2nd Edit: After going through my collection of wall-mounted light fixtures from my previous remodels, I found one with long enough wires that would hang below the painted surface to the tile, so that's what I did. If anyone wants to answer my original question for future reference (or if the mods want to delete my post), but my problem is solved. Thanks for making me think.
 

Last edited by TryAgain; 06-06-15 at 01:48 PM.
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  #2  
Old 06-06-15, 02:11 PM
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Not enough information on wiring to give an answer except to say it was parallel not series. In general though assuming power comes at the box for the light if only the light is removed and the wire nuts put back on the remaining connections the fan should still work.
 
  #3  
Old 06-06-15, 02:32 PM
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There's just one black and one white wire coming out of the wall and into the box. I'm guessing based on its location that the light is at the end of the circuit, but I don't really know that because it's been several years since I've thought about electrical and other than mapping which outlets are on which breaker, I've never really thought about the schematics of this house. (It was built in 1898 and electricity was probably added in the 40s, with some upgrades and rewiring since that time)

Thanks
 
  #4  
Old 06-06-15, 04:17 PM
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If only two wire then just cap them. It won't affect the fan.
 
  #5  
Old 06-06-15, 04:27 PM
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I'm sorry, especially since this is solved, but what happened was when the light was removed and the two wires were just standing there, the fan didn't work. Maybe some other stuff also didn't work, but I know that when I flipped the (hall) switch for the attic fan, it didn't start. When I temporarily put a different fixture in the original fixture's place, after I flipped the breaker, the attic fan worked.
 
  #6  
Old 06-06-15, 04:30 PM
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Don't be sorry..... but if you only connected to two wires then you still have a mystery.
Are you sure there weren't three wires..... two twisted together ?
 
  #7  
Old 06-06-15, 04:37 PM
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There's just one wire of each color. You can see where they come out of old cloth-covered "Romex" and they're pretty stiff, substantial wires. When we took down the fixture, all we did was untwist the wirenut connecting the light to the cable and when I put up the new fixture, I wired it the same way.
 
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Old 06-06-15, 04:45 PM
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Did the light have to be on for the attic fan to work ?
 
  #9  
Old 06-06-15, 04:48 PM
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For temporary lighting when you're painting and such, these are the cats pajamas.
Leviton Weatherproof Socket - Black-R60-00055-000 - The Home Depot

If your fan is indeed wired in series...
If you only have a 2 wire cable at that box, the other end of that cable should be in a place with your feed cable, and cable to your fan. I feel like you would just need to find this common point and switch some joints around.
 
  #10  
Old 06-06-15, 04:56 PM
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In the "states" those are called electrician's chandeliers.
 
  #11  
Old 06-06-15, 05:09 PM
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Never heard that PJ, I always just called temporary light sockets. Yes, they are quite handy.
 
  #12  
Old 06-06-15, 05:30 PM
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Always called them carnival sockets.

If there were only two wires at the fixture box it was the end of the circuit. Not having a fixture would have no affect on the upstream portion.
 
  #13  
Old 06-06-15, 05:55 PM
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That's pretty much what I used, but it was a "fancy" version with a base and a socket going in each direction. I've seen those other things at the hardware store. I had just assumed they were a simple light, but now that I know their use, I'll pick one up.

As for the fan... There's a switch on the hall wall and a fan that fits on the attic access -- when you're going to be using the fan, you move the wooden access cover to one side and pull the fan down into its place. When you're standing in the hallway at the switch, if you look up, there's the fan and because it needs oiled, it makes quite a bit of noise.

I had a fellow upstairs painting and because it got hot this afternoon, I flipped the switch for the fan to the attic. It didn't start, even though it worked fine yesterday and every day prior. The only thing different was that we had taken down a wall-mounted light fixture and left the wires sticking out -- "be careful around these because they're hot" -- and the only thing I did to fix it was wire a different fixture in the original's place. Then, I re-engaged the breaker and flipped the switch. The attic fan started.

PS) And no, prior to today, I hadn't realized the light and fan were on the same circuit. I did start mapping outlets at one time, but then I stopped.

BTW) Thanks for all the replies and now that I know about the chandeliers... great! Thanks!
 

Last edited by TryAgain; 06-06-15 at 06:13 PM.
  #14  
Old 06-06-15, 07:04 PM
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If there were only two wires at the fixture box it was the end of the circuit. Not having a fixture would have no affect on the upstream portion.
I hear you boss, but here is what my brain is envisioning...
He said the fan worked until the light fixture came down. This leads me to believe he may have his wiring done something like so...

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I'm not saying this IS what he is looking at, but it illustrates my point on how this circuit might be wired. If that light is an old incandescent, it doesn't need the neutral to function.
It does sound like the light and fan switch are in series with one another though.
 
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Old 06-06-15, 07:15 PM
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Yes..... that's why I asked about the light being on.

I got tired of people stealing my chandeliers. I switched over to these at half the price.

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  #16  
Old 06-06-15, 08:15 PM
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Interesting, MrAwesome.

I don't know if it has any bearing, but the original light had a pullchain and the wiring was probably from the 40s, while I'm guessing the fixture may have been added ten years ago. The box in the wall is definitely old. I've never seen one like it -- though of course I have limited experience -- but basically the sides look solid, while the back is divided into two "flaps", an upper and a lower. The cable is held in place by the lower flap which is adjustable with screws.

Also, it's rectangular. So, I'm thinking that it may been an outlet and one of the previous owners put the fixture over it. Again, it might not have any bearing, but since we're talking about it, I probably should mention that the fan and switch are like 25' away from the light. (It's an old house)
 
  #17  
Old 06-06-15, 08:31 PM
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The fixture isn't really of much importance. It could be a ballroom chandelier, or one of those pigtail sockets, either way if incandescent bulbs were used it would complete the circuit.
And I don't know why old guys used to do it but I've seen 2104 boxes used behind most of the older vanity fixtures I've taken down instead of o boxes.
Also, even if a receptacle were there at some point it too could have been wired in series and still worked with certain things plugged into it.
Distance between devices doesn't necessarily have anything to do with how things were wired either.
 
  #18  
Old 06-07-15, 06:18 AM
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I am quite sure you do not have the light and fan wired in series (which is incorrect wiring).

A "whole house attic fan" will not work in series with an ordinary light. The light would go on but the fan would turn slowly if at all.

In a series circuit the item requiring the least amperes will get the most of the volts. The volts each gets add up to the supply voltage. The total amperes drawn will not be greater than what the item requiring the least amperes wants and may well be somewhat less than that.

Also the giveaway of a series circuit is both the light and the fan have to be "on" at the same time for either to work. And in most cases the light will be abnormally dim.
 

Last edited by AllanJ; 06-07-15 at 06:57 AM.
  #19  
Old 06-07-15, 11:55 AM
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Allan has a point.
I don't know if I'm going to bite on the operation of the fan, but we don't know if the light was on while using the attic fan.
 
  #20  
Old 06-08-15, 06:10 PM
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FWIW: Prior to this weekend, I didn't know the fan had anything to do with the light. They were operated separately. Until the fan stopped working, I didn't know they were connected.
 
  #21  
Old 06-09-15, 02:23 PM
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If they were operated separately then I'm not sure whats going on there.
 
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