I have an older light fixture with 3 bulbs - each bulb has 1 white and 1 black wire from it, and it also has the standard grounding wire. The fixture box in the ceiling has 1 white and 1 black (and the grounding wire). Do I bundle the 3 black and 3 white from the fixture and then connect to the corresponding color on the ceiling box?
2 Answers
In a word: Yes.
In a bunch of words: Yes, this is called connecting in parallel.
All household lighting loads and most appliance loads operate at the same voltage. So each lamp, fan, toaster, phone charger, etc. needs to be connected between one of the hot legs and the neutral bar in the service panel.
In the case of your lamp, each bulb needs its own separate connection to a hot (120v) supply and a neutral.
The circuit connection considerations of household wiring are very simple, and can be explained in a page of text. Two or three pages with the diagrams. The bulk of an electrician's work, and the content of the NEC, are concerned with safety.
Speaking of safety, you should use two wire nuts for your job. Different manufacturers use different color codes for the sizes, so you need to look at the chart on the packaging to determine the size to use to join one supply conductor to three flexible cords. There is a lot of leeway here. If you can get the nut onto the wires, then it's big enough, and if you can't pull any wire out of the nutted connection, then it's not too big.
(Personally I prefer the one-word answer but American schools have trained me to keep writing until the proctor says stop.)
Yes, all the whites go together, and all the blacks go together.
Lamps are provided this way for a couple of reasons, first it makes the fixture a bit cheaper, and second, breaking out a separate neutral for each bulb it allows the three lights to be on separate circuits or power sources. Think a 3-unit apartment with a shared hall or porch light, so each tenant can turn their bulb on individually. Or one of the bulbs is generator or low voltage DC power.
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Thanks - but to be clear, there is only 1 switch. So all bulbs will be on at the same time - so given that info, the answer is still the same?– JeffCommented Aug 19, 2020 at 17:33
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@Jeff Yeah, that's fine. You can control them together if you like. Separate control is an option, not a mandate. Commented Aug 19, 2020 at 17:44
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1I have often constructed a multi-brightness lamp from such a fixture, with a four-position switch that turns on one bulb, then the other two bulbs together, then all three bulbs. Commented Aug 19, 2020 at 17:47
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@Harper-ReinstateMonica: Seriously, apartment hall lights are typically wired like that? Is that a thing? I could see splitting the bill, but if two of your neighbors are cheapskates with switches, everybody stumbles around?– gnickoCommented Aug 20, 2020 at 2:37
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@GregNickoloff I wouldn't say typically, but yes, I have seen it done. Commented Aug 20, 2020 at 3:19