# wiring basement lighting



## 8roty (Jul 17, 2009)

I'm finishing the basement...... I already modified some wiring (separated ceiling lights into 2 separate circuits with their own switches). The utility area is powered back up and working with the newly located switch. The other lights in the finished area have been removed and have been replaced with canned lights. I have return air through floor joists so I can't take the shortest route between the canned lights, rather than run a bunch of wire to a canned light and back to continue to the next, can I branch off 2 or more lights off of 1 light? See attached basic diagram. 

Second, I made a half-wall at the bottom of the stairs into the basement. The 3-way switch had a wire going up to a light at the bottom of the stairs, this light is in a finished ceiling area so I cannot remove to replace with a longer length of wire. With the half wall I had to run-out the wire further and now the wire cannot reach the exisiting 3-way switch. It can however reach the wiring box for a new smoke detector so I ran the wire there and then extended it to reach the switch. Is this allowed, I'd rather do this than have a junction box.

Thanks in advance for anyone's advice and help.


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## kbsparky (Sep 11, 2008)

Too many wires in that first can light.

Yes, you can hide a splice in the back of the smoke alarm box, provided you have sufficient cubic inch volume for all the conductors.


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## 300zx (May 24, 2009)

Run 3 wire between the two three ways and then one out to light 12-2 then light to light.And power to switch box not to can to many wires in there.


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## 8roty (Jul 17, 2009)

Do I understand correctly, I need 12-2 wire to go to the first can light from 3-way switch #2? Is 14-2 wire sufficient to run from light to light? And must I run wire from light to light in series or can I branch off from one can light to power 2 different runs of lights connected end to end?

Thanks again!


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## KeithM62948 (Jun 10, 2009)

You use #12 wire throughout the circuit if it is protected by a 20 amp breaker, use #14 throughout if it is protected by a 15 amp breaker.

You should be able to branch from one light to 2 seperate runs if there is room in the attached junction box.


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## javier (Jul 18, 2009)

your putting power at the light and the three ways are dead end are you ok on that its a little different so im just asking i can tell you how and you look in the box on the can an see how many wires or how many cubic inches it says


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## 8roty (Jul 17, 2009)

I can re-run the wire to have switch#1 to switch #2 to the can lights. However, is the diagram I posted OK??,..... it sounds like from the responses that there are too many wires in that first can light. The interior of the can light reads: MAX OF 8 NO. 12 AWG (4 IN 4 OUT) THROUGH BRANCH CIRCUIT CONNECTORS.
Does this mean that running 2 14-3 and 2 14-2 wires into that box is OK?


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## javier (Jul 18, 2009)

*basement*

the truth is no if it holds 8 #12 wire that means that box is 18 cubic inches when calculating 14 wire you multiply by two so you have 2 #14-3 so that is twelve cu in then you have 2 #14-2 witch is 8cu in and then the ground is 2 so you have 22cu in


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## 8roty (Jul 17, 2009)

Thanks for the explanation, at first i was really confused with the numbers and calculation but I think I understand it now. So 3 #14-2 wires in a light (1 incoming, 2 outgoing if I make a branch to 2 separate runs of lights) would total 14 cu in?


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## 8roty (Jul 17, 2009)

Here is an updated diagram, everything check out OK?


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## jovingo (Jul 22, 2009)

Much better. The boxes will be less crowded and you will only need one 14-3 cable.


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## javier (Jul 18, 2009)

looks good and easy


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## 8roty (Jul 17, 2009)

When I use an existing box with enough sq in to make a separate connection to extend another run, do the grounds from both runs need to be connected together in the box? I connected them separately but I think I saw somewhere that they should be connected together.


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## jovingo (Jul 22, 2009)

Tie all grounds together and make sure the grounding conductor is also bonded to the box if it is a metal box.


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## DandHJohn (Jul 19, 2009)

For the breaker in a basement application such as this one, should a 15A GFIC be used instead of a normal 15A breaker?


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## javier (Jul 18, 2009)

*no*

not realy we dont do that in indianapolis and i do residential


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## DandHJohn (Jul 19, 2009)

javier said:


> not realy we dont do that in indianapolis and i do residential


So even though it's in a basement, the lighting can be on standard breakers? Convience outlets should be on GFIC's because of the cement floors? I will be installing a floor, but it will be awhile before I can afford that piece.


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## javier (Jul 18, 2009)

*basement*

you could if you want but when we do a finished basement the only thing we gfci is the bathroom outlet


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## DandHJohn (Jul 19, 2009)

javier said:


> you could if you want but when we do a finished basement the only thing we gfci is the bathroom outlet


I've already done that. Thank you for your help.


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## 8roty (Jul 17, 2009)

*gcfi in basement bathroom*

Is it possible to tie in to an existing gcfi circuit when adding the new basement bathroom gcfi? The new gcfi has to be on it's own circuit but can't I share with other gcfi outlets?.... I should be able to tie in to the existing gcfi circuit so I don't have to add 1 breaker for 1 new gcfi outlet. How can I tell if that particular circuit is maxed out? One breaker is labeled as Bath GFI. The kitchen and outdoor GFIs are on other circuits. So with 3 bathrooms upstairs, adding a forth gcfi should be OK. But can it be done?


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## jbfan (Jul 1, 2004)

A bath has to have a 20 amp circuit, that shares all bathrooms, or everything in a single bathroom.


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## 8roty (Jul 17, 2009)

Yes, I am familiar with that requirement. Above the breaker box where the wire comes in for the existing Bath GFI 20 amp breaker/ circuit, can I cut this wire and legally join/ make a new connection and branch to the new run of 12-2 wire to add the basement bath GFI?

***EDIT***
> I started a new thread on this question since the topic doesn't match the question anymore*** thanks


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