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My bathroom has two switches: one [was] connected to two overhead can lights (with CFLs), and one [was] connected to a fluorescent wall sconce (one of those ugly circular plastic things that I can't seem to find on Google). To make room for a ceiling fan in the switch bay and since there is no need for two switches for three lights, I created a single circuit to run all the lights.

Trouble is, the lights won't turn on. The voltage across the circuit is measuring something like 24V. When I bypass the fluorescent sconce, the overhead lights work and the voltage across the circuit measures an appropriate 115V (good enough).

Can wall fluorescents (there are two external ballasts within the sconce; it takes two of these bulbs) be wired into a main overhead circuit? I see in this related question that there's something about them needing to be wired in parallel, rather than in series, but the response is a little hazy to me. If they need to wired in parallel, can they be run on the same circuit? I'd also be happy to replace this ugly little sconce.

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If you hate the sconce so much, don't look a gift horse in the mouth -- just replace it. –  Jeremy W. Sherman Jul 14 '12 at 4:45
$50 and the time it would take to locate an appropriate replacement seem worth trying to learn a little something to address the issue properly. –  kyle Jul 14 '12 at 6:06
The response is saying that you can't daisy-chain the L and N terminals, so no doing feed->Load1->Load2->LoadN. Instead you need separate feed->Load1, feed->Load2, feed->LoadN. This could be done by pigtailing all the conductors to a single feeder. Just be careful not to exceed the circuit and conductor amperage rating. –  Jeremy W. Sherman Jul 14 '12 at 6:14
As Jeremy indicated, loads cannot be wired in series between fixtures (and usually not within either), but need to be run in parallel. Switches are generally the only thing run in series. –  bib Jul 14 '12 at 11:03
Have you noticed any other lights on the same circuit getting brighter when the voltage reads 24V? This can be a sign of an open neutral somewhere –  Steve Jul 14 '12 at 13:28

1 Answer 1

Simple answer to your question is: All load fixtures must be wired in parallel, never in series. This means you need to feed each fixture with 120vac. You can use a single run of wire, but the feed to the next fixture must be wired so that the hot and neutral are always connected uninterrupted to each fixture. Practically speaking, the black hot wire coming from the switch must be connected to the black wire going to the next fixture as well as the black wire for the local fixture in the same wirenut. Same goes for the neutral and ground conductors. This is parallel wiring. If you still have a low voltage reading, then you have a defective ballast or an open neutral.

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