Wiring Multiple Fluorescent Lights

syd81March 27, 2011

I want to wire two 48" fluorescent lights to a single switch.

Is it as simple as wiring them in series or are there other considerations given that they are fluorescent lights?

These are T5 lights suitable for under counter mounting.

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Ron Natalie

Well if you are talking "electrical circuits" you want to wire them in PARALLEL not series. That is all the blacks together, all the whites together, and the grounds together.

If you mean, can you run the wire from the switch to the first light and then to the second, that's also allowed as long as you make the connections in a legal fashion. Many fixtures will allow you to make the connection inside the fixture.

    Bookmark   March 28, 2011 at 5:46AM
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Thanks for the response.

I am curious as to why they have to be wired in parallel?

Is it because of the ballasts?

    Bookmark   March 28, 2011 at 10:02PM
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All household electrical circuits are wired in parallel with each other; there's nothing special about fluorescent lights. This is so that the full 120 volts is presented to each device. If you put devices in series, they will "share" the voltage, say 70 volts to one device and 50 volts to the second (adding up to the 120 volts in the circuit). Neither device is likely to be happy. I'd recommend some more investigation on your part before you start wiring.

    Bookmark   March 29, 2011 at 8:46AM
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There always seems to be some confusion about what in series vs in parallel means in wiring.
In common language, "in series" is generally interchangeable with "in a row." So, many people might see a circuit in which power goes to light 1, then light 2, then light 3 and say they are wired "in series." That isn't what "in series" means in the electrical world. In series would mean that the power came in on the live wire in light 1 and then came out the neutral wire of light 1 and went to the live wire of light 2, and so on. The current would go through the whole series of fixtures before returning on the final neutral.

What you actual want in electrical terms is for them to run "in parallel" - but they are still in a row. So, a live/neutral/ground run to light 1. A live/nuetral/ground run from light 1 to light 2 and from light 2 to light 3. At each light, you join all off the lives together, all of the neutrals together, and all of the grounds together. That way, current it running through each fixture individually or "in parallel."

    Bookmark   March 29, 2011 at 10:04AM
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Do-it-yourself wiring always make me nervous when the question is this basic. I'm not trying to be insulting, but I want you to stay safe. You might consider getting a wiring book or a knowledgeable friend to help on this.

    Bookmark   March 29, 2011 at 1:06PM
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Thanks to all for the responses!

Bill - a special thanks for clearing that up. That was indeed where I was confused.

kudzu9 - Oddly enough, I checked several wiring books and none referred to "parallel wiring" at all - most likely because for the do-it-yourself job, as kurto said, everything is in parallel.

My confusion here came from the fact that I wired two fluorescent utility fixtures in a row (in parallel) they hummed as soon as I turned them on. I was concerned that the humming had something to do with my wiring. In researching whether the fixtures required anything special I encountered some inconsistent advice - which I now know is due to people using "in series" and "in a row" interchangeably.

Anyhow, evidently, my wiring was fine but a bad ballast right out of the box is not an uncommon event.

Again, thanks for all the help!

    Bookmark   March 29, 2011 at 6:49PM
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