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fw2007 06-26-2008 06:05 PM

Too many wires?
 
Hi;
I have a 4" square metal box which has 5 cables, all #12.
I had some difficulty getting the 5 wires together, twisting them before installing the wirenuts.

I was wondering, first off, whether code allows a total of 10 wires + grounds in the 4" box, and second, whether it would be OK to use two wirenuts and a pigtail between to have 4 wires under one nut, and 3 under the other.
4 wires seems so much easier to handle.

What I would really like, is a better wirenut. I thought I read or heard about a "mini-bus" bype of connector where you have a copper bus with several screws, one for each wire.
The entire bus would be protected by a nylon (or other suitable plastic) housing, and finally wrapped with electrical tape. This would of course take up more space in the box than a standard wirenut, but IMO, a much more secure and much less hassle to use.
It would be a nice idea to include such buses in plastic boxes (the larger ones, not regular outlet boxes), eliminating the need to use electrical tape at all.

I do always check the connection by tugging at each wire after the nuts are on, but it's just such a hassle to get them all lined up to twist.

Thanks

FW

fw2007 06-26-2008 06:41 PM

Seems like I answered my own question... again.
I found a chart online that indicates 9 wires for a 4" X 1-1/2" box, but if I add an extension to the box it would then be a 4" X 2-1/2", which allows 13 wires. So am I correct in assuming that I am code if I simply add the extension?

BTW: There are no internal cable clamps in the box.

FW

chris75 06-26-2008 07:09 PM

Quote:

Originally Posted by fw2007 (Post 133943)
Seems like I answered my own question... again.
I found a chart online that indicates 9 wires for a 4" X 1-1/2" box, but if I add an extension to the box it would then be a 4" X 2-1/2", which allows 13 wires. So am I correct in assuming that I am code if I simply add the extension?

BTW: There are no internal cable clamps in the box.

FW

a 4" sq x 1 is good for 21 cu. in, so, # 12 equals 2.25 cu. in per conductor.

so lets keep this simple, 21 / 2.25 = 9.3 wires, you cant have part of a wire, so it ends up being 9 conductors, since you only have to count the grounding wire once, you can have a total of 4 #12-2 cables, OR 2 #12-3 cables.

an extension is required if you want more cables... or want to add a device.

wirenut1110 06-26-2008 07:10 PM

Sounds good to me. I think you're talking about a terminal strip but that would be more efficient in a bigger box. As far the as the wirenuts, a "big blue" would work fine, I think it's a #78 wirenut. I just call them big blues.

220/221 06-26-2008 07:21 PM

"Make up" is all about wire configuation and length. It's not rocket science but homeowners seem to have trouble with it.

5 #12's is full under a red wire nut, but pretty simple.

1. Run all cables into the same part of the box (top, bottom, one side or the other). This allows them to fold up nicely (one bend)

2. Remove PLENTY of sheath (8 to 10"). Give yourself some wire to work with.

3. Separate wires and arrange them one group at a time. Grounds first. Ground box with one of the grounds instead of adding another pigtail to the mix.

4. Use your fingers to manipulate the wires into position. Put a 90 degree bend in them. NOW cut them ALL THE SAME LENGTH. Strip then about an inch. Gather them back together holding them TIGHTLY with all the ends layed in cleanly and straight. Start the wirenut while holding the bundle TIGHTLY. WHen it is TIGHT, fold them neatly into the box. Tuck them back and leave room for the device.

Repeat with the other groups.

wirenut1110 06-26-2008 07:30 PM

As far as a 76 wirenut, it depends whether you're using an Ideal vs. a bcap, a bcap has a little more flexibilty than a hard Ideal. Chris, these are homeowners, as far as "kiss" after he makes up all these wires, he's gonna see "how am I gonna get this cover on?" code is a minimum standard which, in my experience, I'd hardly ever do. Hell, look at conductor fill in conduit, does anyone ever really do this; 16 12's in a 3/4? puhlease.

fw2007 06-26-2008 07:34 PM

I guess it would have been easier with the blue nuts, but I didn't have any. I used the red ones.
I also "pre-twisted" the wires to make a good mechanical connection before securing with the wire-nuts.
Problem I had was that while twisting, one wire would inevitably slip back and then the ends wouldn't be even anymore. I probably should have stripped a bit more insulation, then twisted way more than I needed, and cut off the excess copper. This way, all of the wires reach the end of the splice, even if one did slip back a bit, as long as it's still covered by the wire-nut, it should be OK.

Funny how I think of these things after the job is done.
If I had known what a hassle this would turn out to be, I would have gone into a nearby outlet box instead.

I am going to add the extension to the box.

The kind of bus I was thinking of would be just a smaller version of what we have in the panel box.
I have even thought it would be nice if there were a plastic box with such a "mini-bus" integrated within the box. I guess that would be too expensive<g>

Practice makes perfect, although I kind of doubt I will need to put so many wires in one box again.


FW

chris75 06-26-2008 08:08 PM

Quote:

Originally Posted by wirenut1110 (Post 133951)
Chris, these are homeowners, as far as "kiss" after he makes up all these wires, he's gonna see "how am I gonna get this cover on?" code is a minimum standard which, in my experience, I'd hardly ever do. .


I was shooting for the teaching aspect of it, instead of saying the only way to go is get a 12x12 box for a splice... :wink:

BigJimmy 06-26-2008 08:49 PM

Quote:

Originally Posted by wirenut1110 (Post 133951)
code is a minimum standard which, in my experience, I'd hardly ever do. Hell, look at conductor fill in conduit, does anyone ever really do this; 16 12's in a 3/4? puhlease.

I'm hearing you here. The code tells you what it deems safe not necessarily what may make for an easy or friendly installation. I remember working with this one old timer GF when I was going to school for my engineering degree. We were discussing allowable conductor fills in raceways using table C.8 in the annex section (all RGS on this job) and I was like "wow, you can put 16-12awg's in a 3/4" pipe." He stopped and gave me this look and said, "you ever design anything like that and I'll smack you. Better yet, I'll have you come out and make the pull!"

fw2007 06-28-2008 09:14 AM

Would something like this meet NEC?

http://www.wirenuts.com/prodDetail.d..._blocks_strips

FW

fw2007 06-28-2008 11:50 AM

Never mind. That's not a bussed connector.

I'm just going to learn to use the twist-on nuts properly<g>

FW


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