Adding 2 lights in parallel (one switch)


  #1  
Old 09-01-04, 01:15 AM
Tom M
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Adding 2 lights in parallel (one switch)

I would like to add two new ceiling lights (pendants) that will be connected to one circuit (controlled by one switch). I understand that I need to hook them up 'parallel' as opposed to 'serial' to avoid having only 1/2 the power going to each.

I've looked at a few wiring diagrams to do this and gotten a little confused so I wanted to play back how I understand I should proceed:

I will have a 3 wire source cable coming into a switch. Coming out of the switch will be a 3 wire cable. This will feed into a junction box that will 'split the power' equally (ie a T or Y junction). Net, coming out of the Junction box will be 2 separate 3 wire cables. The first one will end at Light #1. The 2nd one will end at light #2. I tried to draw a sketch (crude, I know), below. Is this correct? Am I close? Any feedback (positive or constructive) appreciated.

Source --- Switch ---- Junc Box ------------ Light #1
..........................................|------------ Light #2


Thanks in advance!
 
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Old 09-01-04, 05:37 AM
R
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Your diagram is correct or incorrect, depending on how you actually attach the wires.

But before addressing the wires, we should discuss the junction box. Why are you using a junction box to split the wiring? Use of a junction box is more time consuming and more expensive. It also means that somewhere there will be a junction box with a blank cover over it. many epople don't like blank covers.

Eliminate the junction box from your drawing, and wire as follows:

Source --- switch --- light #1 --- light #2

Use 12-2 cable or 14-2 cable (depends if a 20 amp or 15 amp circuit). This cable will have a black wire (hot), a white wire (neutral), and a bare wire (ground).

At the switch connect the two black wires to the switch and the two white wires together.

At light #1 connect the black wires together and to the hot wire for the light. Connect the white wires together and to the neutral wire for the light.

At light #2 connect the black wire to the hot wire for the light and connect the white wire to the neutral wire for the light.

At all places connect the ground wires together and to the switch or light, and to the boxes, if metal.
 
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Old 09-01-04, 05:40 AM
W
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You are essentially correct. Some of your description seems a bit fuzzy, which suggests that you should read a home wiring book to become more familiar with the various details that can get you with home wiring.

I presume that by 'three wire cable' you mean standard 12/2 with ground or 14/2 with ground.

In the switch box, you would have two cables, each with white, black, bare.
Splice the whites together.
Place one black on each of the switch terminals
Splice the bares together with a bare pigtail, and run the bare pigtail to the switch ground terminal.

In the junction box, you would have three cables, each with white, black, bare.
Splice like with like, white to white, black to black, bare to bare. Three wires in each wire nut.

Note that each light fixture needs to be mounted on an outlet box, which can also serve as a junction box. So your cable could run from the switch to light 1, and then from light 1 to light 2. You are correct that the lights must be electrically in parallel, rather than in series, but electrically in parallel depends upon the connections of the _wires in the cables_, not to the overall layout of the cables themselves.

Note also that there are lots of details that I am sure to have left out....get a good wiring book and read it, and then come back with any questions!

-Jon
 
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Old 09-01-04, 07:42 AM
J
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I agree with Bob that the junction box is unnecessary, a complication you don't need, an extra possibility for error, and an annoyance to ensure that it remains permanantly accessible.
 
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Old 09-01-04, 01:45 PM
Tom M
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All -
Thanks for the replies...

Racraft/Bob - Your description/simplification makes sense... That is the way I originally thought to do it.... But I'm not not sure why this wouldn't be considered a 'serial' connection. How would a 'serial' connection differ from what you proposed?

I'm not saying I want to hook the lights up in serial - I'm just curious what the difference would be.

Thanks again!

tom
 
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Old 09-01-04, 02:49 PM
R
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Using the words serial and parallel to describe electrical circuits gets you into trouble.

Simply put, all of your devices on a circuit are electrically in parallel. That is to that each device gets 120 volts across it.

Now to do that you can run the cables anyway you choose. You can run the cable serially from one device to the next, to the next, or you can run two cables from one junction box, one to each light. As long as the devices are properly wired.
 
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Old 09-01-04, 02:50 PM
J
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Since virtually everything in your house is wired electrically in parallel, most of the time people use the word "series" to refer to cable routing rather than electrical connections. Wiring things electrically in series has almost no useful application in home wiring. To avoid confusion, I prefer to use the term "daisy chained" to refer to cable routing that goes from A to B to C to D to E. That way, the word "series" is equivalent to the word "wrong">
 
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Old 09-01-04, 07:02 PM
Tom M
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John & Bob -
Thanks for the clarifications... Your explanations made perfect sense.
tom.
 
 

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