[jlh2001]

I have 3 rooms in my basement that will contain 4 recessed lights per room. Each room will have one wall switch to control the lights per that room. The power will come from a new single 15amp feed from the sub panel. Could you provide an easy to follow wiring diagram/explanation on how to hook this up. Thanks, John

[donf]

To begin with, will a 15 Amp circuit be able to drive 12 individual lights? Have you correctly sized the load for this circuit?

To begin with, I would suggest that you pull 12/cable from the sup panel to the first outlet in the first room. Do not connect the new cable now. Make it the last thing you do.. At this outlet, again using 12/3 run a switch loop to where the first switch goes.

At the overhead outlet, the black from the sub panel connects to the white from the switch. Wrap a small amount to black tape to signify that this wire is now carrying voltage instead of being a neutral wire.

Black from the switch got to black from the first light from there on, black will go to black and white to white until all four lights are chained together.

Back at the overhead, do two pigtails, one for the power source (Black from the sup panel, white to the switch and black for the next room). The second pigtail is for the whites.

Continue your daisy chain until the three rooms are finished. Shut the sup panel down add the wire and breaker into the sup panel, turn the breaker on and test your rooms

[labman]

I would be just as happy to leave electrical questions to somebody that can give good answers. I still wouldn't questions like this, but I am afraid somebody would take the bad advice before somebody else corrects it. The answer above has some problems just as several of his have. Lights are frequently run on 15 amp circuits. As long as you are planning on using less than 120 watts per fixture, it will be OK although with little margin. I hope you aren't planning on using soon to be regulated out of existence incandescents. Besides the popular CFL's, there are halogens and even LED's. Little down side to going ahead with #12, but you will want 12-2 or 14-2 with ground. 12-3 suggests a third, insulated conductor, and Donf gives no instructions for what to do with the red wire it would have.

Donf and some others here seem to have an obsession with switch loops. Yes, they make sense in some cases. It might be easier in your case to just run the power to the closest switch, and then to the next and the next. Then run power from each switch up to each string of lights. How you do it might depend on whether the walls or ceiling are finished.

I may have missed something, so don't buy any wire until tkrussel checks in.
Maybe he understands why you would need 12-3.

[donf]

Labman,

I have an obsession with switch loops? He defines his room as 4 lights and one wall switch. If he doesn't use a loop to tie the switch into the circuit how is it going to connected?

12/3 is a typo. 12/2 is correct, thanks.

[Stratmando]

Like labman says, I would run from panel to first switch box, then 2 romex's out,(one to that string of lights,the other to next switch, from that second switch box, 2 more out(1 to that string of lights, the other to the next switch box. Personally I hate romex, I would use "Smurf" ENT(Electrical Non Metallic Tubing).
I would consider recepticles, and smoke detector(s).

[labman]

How much extra cost and work is smurf over NM? I think in most residential work it is a knee jerk reflex to use NM. The only time I can remember of venturing out of it, was the dog resistant feed to my A/C where I used rigid steel. So far, none of them have chewed it up. One thing about any conduit is you can pull what ever you need, black, white, red, green, purple, etc. and never need to remark a white wire that was paired with a black. Where a switch loop is what works best, just pull a couple of blacks or a red.

[donf]

If JLH is going to leave the wiring exposed on the walls and ceiling, then by code the wire must be run inside conduit. If he is going to frame the walls and dry wall over the frame, then NM Cable is the way to go, again by code. Or am I looking at a code book from Pluto?

JLH, please chime in with how the wiring is to be installed as soon as you can.

[Stratmando]

Hate Romex, Code does not say smurf is a violation. It allows future growth, ESPECIALLY
If wireing is covered with drywall. I think some people use romex so much, it is a habit.
I like conduit, it is a habit. Don't like destroying walls to add a?? a wall AC or something.

[donf]

I don't know why you hate NMB cable, it certainly has it's designed purpose. Nor did I say that "SMURF" is a code violation.

What I did say was that if the wiring is going to be exposed, it must be wired in conduit. Conduit in this usage means metal or PVC.

Also, if the wiring is going to be behind walls, then NMB wiring is allowed. It matters not to me if you want to place PVC behind the walls and pull wires. It just is not required by code to place PVC conduit behind walls in a residence. Commercial buildings are a different story.

[Stratmando]

I know its not required, just makes things easy in the future, to pull additional wiring.
Romex does have it's purpose, its fast, cheap, especially with copper prices.
It is more difficult to add even just 1 wire. I feel it is obsolete, the minute it is installed.
Poster can use what's allowed? Good Luck

[donf]

NMB is certainly not obsolete. Don't even think that, I just bought some stock in Romex :)

Seriously, I would appreciate your expanding your reasons and observations about the benefits of Smurf over NMB.

I want to learn, not squabble.

[Stratmando]

Future upgrading, some Automation stuff need neutral or a constant Hot, in box.
It is not Obsolete. I have ran a pair of wires through fan boxes, switch boxes, and through recepticles to get 3 wall unit AC's to 3 bedrooms. Romex would have been impossible.
Wall would have to be destroyed, patched, painted... and on.
I will try to say it clearer. Once romex is installed, I feel it is obsolete. Not easy to simply pull an extra wire. I also like stranded wire, as I feel it is less stressfull on devices(Physically).
If this is only 3 rooms, and only needs lights, and will never need a heater, recepticles for convience, maybe a wall AC, then romex is OK. Tnen it is obsolete?

[shader]

It appears a lot more info is being posted here than asked for. The original poster only asked for a wiring diagram/explanation on how to hook it up, not recommendations on what type of wiring materials to use-though some valid points are noted.

donf-there are simpler ways to wire this type of circuit. What's disconcerting is that in several of your posts you state that you're not a code expert or an electrician, and would defer your answers to electricians who post, yet you freely cite the code and give wiring advice. The code is very complex and many of the articles have exceptions. I know you're trying to be helpful, but posters come here for sound and correct advice, not what people "believe" or "suggest".

And a final thought on "code"- Just because a particular application is allowed by a "national code" doesn't mean it will comply with local codes-some are stricter. Notice tkrussell disclaimer? If it's a small project and with no permit pulled maybe OK. On a larger project problems could arise when selling the house, insurance claims, etc---just FYI

[pelle]

3 rooms with 4 can lights in each room that is a total of 12 lights even at 100 watts per light it would equal about 10 amps so the circuit breaker will be fine. 14/2 wire is fine this wire will contain 1-black, 1-white and a bare copper wire.
The power will have to run to the first room into a switch box. From this box 2 more wires will be needed... 1 will go to the first lite fixture in this room the other will go to the next rooms switch box.. The wire in the lite fixture box will connect to this fixture and another wire will run to the next fixture box.. Connect all the whites together all the blacks together and the bare coppers.. be sure to use the correct connectors..

Now for the switch box. There should be 3 of each color wire in this box.. the white get all connected together use a red wire nut and tuck these into the box.. the black from the panel and the black to the next switch box and a short piece of black (5" approx) get connected use a red wire nut .. now you should have 2 black wires and all the copper .. The 2 black wires should be 1 5" piece that is connected to the main panel and the next switch wires and the one black going to the light fixtures.. take these 2 blacks and connect them to a signal pull switch (ordinary lite switch).. take the copper and twist them together and connect 1 of the strands to the switch green screw

[abcsalem]

It was mentioned in the previous post that, if the original post member uses 100w light, then 12 of them on 15A breaker is fine.
Question: Considering the 80% design capacity rule,
When it comes to placing only lights on a breaker, what size light (MAX) can one
To assume, so that one can calculate what breaker size and wire size to use?

[pelle]

12 lights at 100w is 1200 watts divide this by 120v is equal to 10amps using ohms law
which is amps = watts divided by voltage.. so 10 amps is 66% capacity on a 15 amp circuit..

[abcsalem]

12 lights at 100w is 1200 watts divide this by 120v is equal to 10amps using ohms law
which is amps = watts divided by voltage .. so 10 amps is 66% capacity on a 15 amp circut ..

That's understood. The question was, what size, i.e. how much watts per light socket one needs to assume when figuring the total wattage for a breaker? Do electricians assume
People would go maximum of 100watts light bulb in a residential settings per light socket?

[labman]

Many fixtures specify 60watts max.

I do want to point out Pelle is just as wrong where he insists the feed must be to the switch as Donf is where he insists it must be to the light. As I said, either way is safe, workable and code compliant. Usually I would go with feeding the closer one to save time and wire.

[Flying Blue Eagle]

I go along with 9Donf ) answers he has it down pretty close .

[labman]

I am very disappointed in many of your answers as well as his. We have a top notch electrician here. I would like to see more questions left for him if people can't get things right.