Wires in conduit

[Unregistered]

How many 12 gauge wires can I run in 1/2" conduit and 3/4" conduit?

[mdshunk]

You can run nine 12 AWG conductors in 1/2" pipe and sixteen #12 AWG in 3/4" pipe. This is max by code, but not very much fun to pull in if you have a couple of bends or offsets. Don't skimp on the conduit size... you don't know what the future holds. Using 3/4 where 1/2 would do, isn't going to break the bank and will make your life easier. Remember too, that there's no more than 360 degrees of total bends allowed between pull points (four nineties or six 30 degree offsets, or the equivelant).

[Speedy Petey]

Also don't forget the fact that with over nine current carrying conductors in a conduit the derating amps go downhill fast.

[rlfrazee]

Doesnt the insulation type for the wire he is using matter? Also he doesnt say what type conduit, EMT, Rigid, IMC,...etc....not questioning guys. I'm not a licensed and schooled electrician just curious ......RL

[mdshunk]

It matters a little. What I quoted was for THHN in EMT. Generally, THHN is what's going to be pulled. Fills for EMT are darn close to fills for other systems. Table 1 of the code is the "official" way to calculate fills, but it requires you to do the math. ANNEX "C" has done the math for you if all the conductors are of the same insulation and same gauge. I think when fills are ask for generically, as this person did, THHN in EMT is a safe bet for the answer (if anything a bit conservative if, for instance, PVC is used instead). But, you're right, insulation and raceway type does matter for the most technically accurate answer. The wallet cards that the supply houses give out for conduit fill quick reference generally show fills for THHN in EMT.

[rlfrazee]

Mdshunk, I see what you mean now that you mention it. Checking the tables I see that for THHN it stays pretty close from one conduit to the other. THHN is pretty much the norm here at the electrical stores for this type application as you said. Plus EMT requires few specialty tools and easy to work with so probalby what most use ......RL