Kitchen Remodel (conduit and Wiring)

mark_anderson_usNovember 27, 2010

Hi All

I'm about to embark on a kitchen remodel. The house is 1912 and has a lot of knob and tube and old AC with cloth insulation. I'm in Chicago so have to use pipe for everything. I have full access in the basement so will be running a 1" pipe around perimeter. While I have access to the stud bays, I will run EMT from the basement to the 2nd floor to replace existing recepticles and add new ones.

I have a few questions

As I don't have access to the end of any stud walls, running pipe between the studs would be a lot of short sections and connectors, so I figured I'd run vertical emt from the 1" pipe in the basement (lots of junction boxes).

1st question

is this a better method than running lots of short pieces? If I were to run between studs from box to box, would I run conduit at the center height of the boxes (so I come out of right side of one box, through a stud and into the left side of another box).

2nd question

Can I just pigtail the wire to the recepticle in the JB on the floor joist? So I would cut the incoming wire, pigtail the wires for the recepticle (2-4 feet above) and also pigtail the outgoing wires to the next recepticle. Or, do I have to run the wire up to the recepticle, pigtail in its box and then run it back down?

3rd Question

As there will be many circuits in the 1" perimeter conduit, can other circuits pass through a jb where I make a pigtail. For example, the dishwasher and one of the small appliance circuits share the same run for much of the distance, so I would be running the dishwasher circuit through 3 jb's that have vertical runs to outlets above. Is it OK to pigtail the wires for the small appliance recepticles and have the dishwasher circuit pass straight through those JB's



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Ron Natalie

1. Shorter runs make easier pulls
2. As long as the boxes remain accessible you can do either.
3 How many circuits? You have to watch the conduit fill. You only get 9 #12's in a 1" (and even then it's going to start getting fun to pull. Then remember once you get more than three current carrying wires in a conduit derating comes into play.

    Bookmark   November 27, 2010 at 12:20PM
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Answer #1: Probably, given your description of the construction. Neither method is inherently "better" - both have their ups and downs, but if you simply CAN'T run short pieces in between, then that kinda forces your decision anyway.

#2, yes, you're making a junction, which is what junction boxes are for.

#3, yes. The primary consideration is going to be box/conduit fill, but there's no prohibition against multiple circuits in one conduit or box.

    Bookmark   November 27, 2010 at 12:36PM
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I would not pull RHH with outer covering. Is this some Chicago rule that I am unaware of? I would pull THHN and you can use 26 of them in a one inch. I would also probably only use (2) 3/4" EMT and run one around each side, according to how many circuits. I would also run larger circuits like the range or ovens and cooktop seperately.

    Bookmark   November 27, 2010 at 12:44PM
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I would run 3/4" because it is easier and cheaper to find boxes for it.

    Bookmark   November 27, 2010 at 12:51PM
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The maximum current carrying conductors in a conduit before you need to derate is 9.

    Bookmark   November 28, 2010 at 10:59AM
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"The maximum current carrying conductors in a conduit before you need to derate is 9."

But you also need to keep in mind that the derating for #14 and #12 is NOT 15 and 20 amps respectively.

    Bookmark   November 28, 2010 at 12:02PM
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The maximum number of current carrying conductors before you need to derate is three, but that is beside the point. Does anyone here think the op would need one inch conduit to begin with? With only two 3/4" conduits and nine or fewer ccc's in the conduit (so you don't have to increase wire size for 20amp circuits) you could run up to twelve 20amp circuits, which I would think would be more than needed in most kitchens. I have done some pretty large kitchens on eight 20amp circuits. My point is that you don't have to overkill a job on pipe size when it will only cause inconvenience if not problems. I would use combination 1/2" and 3/4" knockout deep boxes and use 1/2" conduit on the stubups to the wall boxes. Just because you are doing it yourself does not mean you need to install overly large conduit. You will still need to increase wire size after 9 ccc's in 1" conduit as well.

    Bookmark   November 28, 2010 at 1:47PM
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You derate after 3 conductors. However derating starts a 20amps for #14. Therfore you don't drop below 15 amps until you have over 9 conductors.

    Bookmark   November 29, 2010 at 9:28AM
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Hi guys

Thanks so much for all the useful info and advice.

Based on feedback, I think I'll do 3/4" around the perimeter (in basement) and 1/2" for stub ups. Separate conduit for electric oven

One other question:

Can I come out of a JB in basement to several outlets (so for a run of 3 outlets, I'd come out of JB on pigtail, go to 2 middle of runs and then one end of run) and the same on another JB on the same circuit?

    Bookmark   November 29, 2010 at 1:10PM
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