Flourescent light flickers when OFF, doesn't always start


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Old 03-06-10, 11:56 AM
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Question Flourescent light flickers when OFF, doesn't always start

A little background - I'm installing some new flourescent fixtures (circle tubes) in an older home with aluminum wiring. The circuit I'm working on has two fixtures connected in series. The first fixture after the switch doesn't turn on sometimes and then flickers when the switch is turned off. After several tries the light will come on normally and doesn't flicker after the switch is turned off. I was checking around the web and noticed a thread about the neutral wire being wired incorrectly to the switch and I think that's the case here. FYI, I am using the gel for the aluminum wiring. Here is a pic of the switch, notice it has a red wire and then a neutral and hot spliced with a wire nut.



Then there is the fixture location, notice the two black wires spliced with the white.



From there it's just a black and white wire going to the next fixture in series which works just fine. Any suggestions to stop the flickering when turned off and have the first fixture start normally every time? It's old aluminum wiring from the 60's and the switch looks pretty old as well. Thanks in advance!
 
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Old 03-06-10, 02:28 PM
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Aluminum wiring has special procedures that need to be followed. Please make sure that is done.

Your wiring looks to me to be correct. The cable that has the white tied to a black is nothing but a switch loop. The white in the ceiling is the hot, down to the switch box in the picture tied to the black. That black is going to the common terminal of the three way not pictured. The white and red are the travelers back to the three way pictured. The common of the switch pictured is attached to the black of the switch loop back to the ceiling box and that is your black with the pig tail. The other light box not pictured should only have 3 wires (unless other stuff is spliced through)

I would make sure all your connections a good. If so, I would suspect your fixture is going bad. Or you have a dimmer or lighted switch on one of the three ways.
 
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Old 03-06-10, 03:27 PM
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Thank you, Tolyn Ironhand. The last fixture does indeed have the three wires - white, black and ground. The only special procedures with regards to the aluminum are the use of the gel on the dissimilar wires when spliced. I brushed the wires, dipped them in the gel and also filled the wire nuts with gel. Not sure what else is required other than pigtailing with solid copper. The fixtures are new but perhaps one of them is bad - my understanding is they were sitting around for a long time (possibly years) before I installed them.
 
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Old 03-06-10, 05:32 PM
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The fixtures being old new stock suggests they have magnetic ballasts and fire T12 lamps which won't be manufactured much longer. Magnetic ballasts have long had flickering complaints, but may not be the problem you are experiencing. I'd do a couple of additional things to be assured of trouble free operation. First, the connectors you are using appear to be Scotchloks. These are not approved for aluminum wiring. You mentioned dissimilar wires. If you mean copper to aluminum wires, the Scotchloks are not approved for this either. Merely filling the connectors with anti-oxidant compound is not the right thing to do. You can purchase connectors approved for aluminum to aluminum or copper to aluminum connections from Ideal, they go by the tradename of Twister and are usually purple. Second, the picture you posted shows the aluminum wires back stabbed in the 3-way switch. Back stabbing is notorious for bad connections which may be a big part of the problem you have. Try using the screw terminals and be sure the switches are marked COALR meaning they are approved for use with aluminum wiring.
 
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Old 03-06-10, 06:49 PM
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Originally Posted by CasualJoe
The fixtures being old new stock suggests they have magnetic ballasts and fire T12 lamps which won't be manufactured much longer. Magnetic ballasts have long had flickering complaints, but may not be the problem you are experiencing. I'd do a couple of additional things to be assured of trouble free operation. First, the connectors you are using appear to be Scotchloks. These are not approved for aluminum wiring. You mentioned dissimilar wires. If you mean copper to aluminum wires, the Scotchloks are not approved for this either. Merely filling the connectors with anti-oxidant compound is not the right thing to do. You can purchase connectors approved for aluminum to aluminum or copper to aluminum connections from Ideal, they go by the tradename of Twister and are usually purple. Second, the picture you posted shows the aluminum wires back stabbed in the 3-way switch. Back stabbing is notorious for bad connections which may be a big part of the problem you have. Try using the screw terminals and be sure the switches are marked COALR meaning they are approved for use with aluminum wiring.
They are T9 lamps with electronic ballasts, so that is not the problem. You are correct about the scotchlok connectors and the back-stabbed connections into the switch, I am planning on changing these now. This is the existing setup btw. The switch is AL/CU rated, its the existing switch that has been there for many years. Jiminy Christmas the purple Twisters are expensive here! $5.47 for two lol. I'm also looking around for AlumiConn connectors, might be a better fit in the tiny boxes these fixtures/switches have. I'd kind of rather go with the AlumiConn as they will fit better, its all I can do to cram the existing splices back into the old-ass (bake-lite?), tiny boxes here. What a pain lol. Thanks for the advice and I'd appreciate any other advice offered :-) Oh and by dissimilar it is going from Aluminum-to-Copper. House was built in the 60's.
 

Last edited by n0c0sm0s; 03-06-10 at 06:53 PM. Reason: add info
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Old 03-07-10, 07:14 AM
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Originally Posted by n0c0sm0s
The fixtures are new but perhaps one of them is bad - my understanding is they were sitting around for a long time (possibly years) before I installed them.
I would suspect the lamp before the ballast. You can swap the lamp between the fixtures to see if the symptom still exists.
 
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Old 03-07-10, 09:04 AM
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I would agree, the purple Twisters are very expensive, but anything made specifically for aluminum branch circuit wiring is expensive. I would also agree with suspecting the lamp before the electronic ballasts.
 
 

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