DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Electrical (http://www.diychatroom.com/f18/)
-   -   How to wire multiple lights in attic on same circuit? (http://www.diychatroom.com/f18/how-wire-multiple-lights-attic-same-circuit-104226/)

bottlerockett 05-12-2011 02:07 AM

How to wire multiple lights in attic on same circuit?
 
Hi all,

I'm a newbie attempting to replace knob and tube wiring in my attic for the overhead lights in my foyer, living room, kitchen, etc. Six lights in total (one is a ceiling fan) will be on one new, 20-amp circuit, using 12/2 wire. Each will have its own switch.

Can someone please describe for me the specifics of how to connect the wires for this setup? (e.g., "Connect the black from the panel and the black from the second switch box with the pigtail...")

I think I want to run power to the light fixture first, rather than the switch, since, in the attic, it seems like the easiest way to route the wires. Does that mean I need to splice three different wires at each light fixture (one from power, one to switch, one to the next light)?

I keep referring back to this thread and the great answer from Chris, which shows how to do this when you run power to the switch first:

http://answers.yahoo.com/question/in...4050322AAaeWgQ

But again, seems like running power from switch to switch will create more of a maze of wires in my attic. Is one method better than another?

Just hoping someone can explain the detailed wiring setup for this scenario. FYI, I already understand the basics and code on how to route wires in the attic (been reading my Home Depot wiring manuals, plus lots of other forum threads). Thanks in advance.

Don

joed 05-12-2011 09:05 AM

You can't do what you want with 12/2 cable. You would need some 12/3 cable. Unless you want to go buy some 12/3 cable you will need to go to the switch first.

bottlerockett 05-13-2011 02:25 AM

Hey, thanks joed. So regarding power-to-switch vs. power-to-light-fixture... is one method more common, or more preferable to the other for any reason, in an attic scenario?

Don

sirsparksalot 05-13-2011 02:51 AM

The attic setting has nothing to do with it. Personally, I go to one of the switches first, because it's easier for me to grasp.

I read the link you provided, and it appears correct.

sirsparksalot 05-13-2011 02:52 AM

BTW: 14/2 (instead of 12/2) is good if you haven't already bought the 12 AWG

thadsaab 05-13-2011 07:32 AM

Quote:

Originally Posted by sirsparksalot (Post 646895)
BTW: 14/2 (instead of 12/2) is good if you haven't already bought the 12 AWG

Only if he also makes this a 15 amp circuit instead of 20 amp.

joed 05-13-2011 08:41 AM

Quote:

Originally Posted by bottlerockett (Post 646892)
Hey, thanks joed. So regarding power-to-switch vs. power-to-light-fixture... is one method more common, or more preferable to the other for any reason, in an attic scenario?

Don

The way that uses the least cable is the way I do it. Of course there are new code rules requiring neutral wires in the switch box so switch first often becomes the way.

bottlerockett 05-15-2011 01:34 AM

Hey, thanks all. I'll wire it switch to switch. Went up in the attic and the routing makes sense to me. What's great is that there are already holes in the joists where the current knob and tube runs, so I'll have very little drilling to do.

bottlerockett 05-31-2011 11:34 PM

Hey all,

I'm in the middle of this job, and it seems like I can't possibly cram all the wires I'm using into a normal switch box, and still be up to code. Can you help? How would you do this? To refresh, I'm rewiring the overhead lights in my house on a new circuit, replacing knob-and-tube. In each switch box there are three separate runs of 12-2 Romex (from power, to light fixture, to next switch).

I just did this for one light and I had to pack the wires into a normal metal switch box (3"x3 1/4"). It was hard, especially since I left each wire 8" long. By my calculation, that's 10 wires in the box (6 insulated wires, 1 for ground, 2 for the switch, 1 for metal cable clamps), which seems to be too many for any single-switch box.

What should I be doing here to be in code compliance? Fitting wires in a larger two-gang switch box, but the second half of it is hidden behind the plaster wall? I'm confused. Any guidance appreciated.

sirsparksalot 06-01-2011 12:31 AM

You need a 22.5 cu. in. switch box. They come in single gang. Carlon makes th plastic Blue box: B122A
http://www.carlon.com/Installation_T...Wiring_Box.pdf

bottlerockett 06-01-2011 01:18 AM

Ah, thanks! Didn't know they made a single box that big. Cool.

One more question: Since the plastic boxes don't have wire clamps at the back (just pop-through ports for each run of Romex), does code require me to fasten the wire cables in some other way, to a stud behind the wall or something? so there's no possible tension on the wires in the box.

sirsparksalot 06-01-2011 01:26 AM

Quote:

Originally Posted by bottlerockett (Post 658947)
One more question: Since the plastic boxes don't have wire clamps at the back (just pop-through ports for each run of Romex), does code require me to fasten the wire cables in some other way, to a stud behind the wall or something? so there's no possible tension on the wires in the box.

yes, it should have the first staple (I believe) within 6" from the box.

SD515 06-01-2011 09:24 AM

Fastening required within 8" if the box doesn't have clamps, 12" if the box has clamps.

sirsparksalot 06-01-2011 02:20 PM

Quote:

Originally Posted by SD515 (Post 659096)
Fastening required within 8" if the box doesn't have clamps, 12" if the box has clamps.

Kyle, I tried to find this in the Code, but couldn't. All I could find is the exception listed in 314.17 (C) Nonmetallic Boxes and Conduit Bodies, but that references UF cable. I know it's there, where in the Code can I find this?

Jim Port 06-01-2011 03:19 PM

Try 334.30 also. The 314.17(C) exception lists both UF and non-metallic cables into single gang boxes non-metallic boxes. If a metallic box was used it would be clamped.


All times are GMT -5. The time now is 07:34 PM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved