Hi,
I just want to double check the wiring in one of our bathroom junction boxes. The box is 34 ci. We have a toggle switch and a double switch w/timer in the box. There are 4 x 14-2-g and 1 x 14-3-g wires. By my calculation, this box should be adequate. I had replaced the original box with the current box that is slightly bigger. The reason I have concern is because the new double switch w/timer (Pass & Seymour DEFL44L) takes up a lot of volume, and the wires just seem more cramped than might be allowed. But, even if I give the switch a 3 instead of a 2 for standard switches, I’m still in the calculated rating. Am I correct?
Thanks,
Ryan
Replies
bump
94969.19
In the beginning there was Breaktime...
94969.1 Photo Gallery Table of Contents
Oh boy, do you have a copy of the NEC? If not, I do. Box fill is what you are looking for, but I can't remember which table it is. I know you count the grounds as one conductor, and the neutrals and hots individually. I'll give it a minute for someone less lazy than I, and then I'll go look it up for you.
Yeah, I'd look it up but there are too many fine-print exceptions that I'm likely to mess up on. But my experience has been that if you can get the wires back in the box without a sledge hammer you're probably not over the limit.
There should be a wire fill table. You have already calculated cubic inches, so all you do is look at the table to see how many conductors can fit. If you have questions about terminology, don't hesitate to ask.
Thanks for the replies. My understanding (according to the NEC fill chart) is that since I'm using 14g wire, each wire needs 2ci. All grounds combined = 1 wire, and each switch or receptacle is equal to 2 wires. So, with 4 x 14-2 and 1 x 14-3 I have 11 wires + ground which makes 12 total. Then I add in the 2 switches and I get 16. Multiply by 2ci and I need 32ci, and I have 34ci. The concern is that the combo switch I have is much larger than a standard switch, and there is no recommendation to account for that. So I just want to see what others think.
Thanks,
Ryan
1) Legal, calculation is correct. Unless there is something not mentioned like internal cable clamps.
2) May be a bit cramped - be neat and plan in advance and you should be fine. One thing I always avoid in this type of situation is winged wire nuts - they seem to take up more space when you go to tuck them in.
JimNever underestimate the value of a sharp pencil or good light.
I suppose we have all gone through this. I did a bunch of GFI receptacles in one building and yes it was cramped in the boxes.
I did put pigtails on them so if there was a problem with the receptacle it could come out more easily. But the pigtails take up a little more space.
"each switch or receptacle is equal to 2 wires."No it is each Yoke or Strap that is counted. Not the number of functions on that strap.So you are OK..
William the Geezer, the sequel to Billy the Kid - Shoe
Use Wago brand Wallnuts. They are much smaller but they only have 4-way or 8-way (up to four or eight wires). They are much smaller than wirenuts, and may favorite, no wire twisting. The conductors just pop right in. Make sure you don't have any bare copper sticking out the back, though, and that you have enough copper in the Wago.