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how to wire multiple lights and switches on one circuit

45K views 9 replies 4 participants last post by  gregzoll 
#1 ·
Perhaps I'm thinking way too deeply, or not hard enough, but I was wondering if it's possible to run multiple switches/lights off of one circuit? I guess an obvious way would be a junction, where each switch/light combo would have a wire coming from, but that's probably not the most cost-effective way.

This is for lights in different rooms on the same circuit (not a 3-way system).
 
#2 ·
It is done all the time. You should look for a book about home wiring. There are several out there that can give you examples of how to wire things. There are just too many different ways to do this to try and explain. The simple explanation is the you bring power feed to each switch and then to the lights. Power can go in one switch box and out to the next one.
 
#4 ·
First, how many switches, 2nd, how many lights do you plan to wire in, and what wattage of bulb. That would be the first two things to decide if either it will be a single 15 or 20 amp, or need to be 2 or more circuits. Check with your city hall, because they would be the last deciding factor, regardless what the books state. I use the Black & decker Complete guide to home wiring, latest one for the 2011 NEC comes out around June, currently they are publishing with the 2008 NEC.
 
#5 ·
Looking at 5 - 6 lights, no more than 480w total (and that is a huge overestimate, and 2 of those lights will be outdoors using 26w cfls), plus one or two receptacles in a small hallway on the 2nd floor. Was already thinking of 20 amp 12/2 wire for this.

Worse case is a total of 78w per light fixture (3 26w cfls per fixture, but that is just overestimating for safety).
 
#6 ·
Outdoor, I would come off of a GFCI circuit. The receptacles in the hall should come off of a bedroom circuit. As for lights, if they are in bedrooms, you can come off of the circuit for the outlets, same for living room. The way I did my lighting for my two bedrooms & hall light when I rewired my house, is had them come off of a separate circuit, since they run ceiling fans pretty much 24/7 in the bedrooms, and hall light only goes on when you get in the pantry or linen closet.

It is easier to sit down, draw out the floor plan, then lay out how the circuits are, following also the NEC guidelines regarding GFCI & AFCI circuits.
 
#7 ·
Do the outdoor lights need to come off a GFCI if they're under a covered porch? If so, I'm guessing a GFCI receptable before the lights would be acceptable for this, correct?

The way this 104 year old house (supposedly, even though the rafters have "Oct 1867" painted on them) was built (no studs, just fire blocking and top plates that bear on corners), I want to pull my hair out. Currently I have the entire first floor ceiling removed, and have been running wire along the floor joists and can easily run wire through walls on the secondn floor this way (still have to drill through the fireblocks though). I've got wiring setup for a 20amp circuit for 2 of the 3 bedrooms that are on the 3rd floor. Next up is just figuring out how to power up the 2nd floor hallway light and the first floor living room/dining room lights, which is what I was hoping to figure out here. Thanks for the tip on the GFCI though for the outdoor lights. Definitely will remember that.
 
#10 · (Edited)
My house was wired in from the basement to the back bedroom, from there to the bath and the hall light and feed for front bedroom. Other half was kitchen wired from a box in the basement, feeding back door light, dining light. Living room outlets feed the front door light, entry light, and ceiling light in living room. The living room stayed 15amp, along with bedrooms, since those rooms did not need that much for receptacles, plus redoing the ceiling light & entry/front door lights would be a ***** with Rock lathe.

Tonglebeak, if it was me, I would pull #6 up to the second floor to put a sub up there for that floor, so that you do not have to go down two flights to flip breakers if something trips a circuit
 
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