How much wire in 1" conduit?

Old 10-27-03, 08:26 PM
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How much wire in 1" conduit?

How much wire can 'easily' fit in 1" conduit???

I have extremely limited space in one area. I would like to put 1 10-gauge w/ground, and the rest 12-gauge.
Old 10-27-03, 08:35 PM
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if you are planning to stick the NM wires inside the conducts ??

first 24 inch is ok but for whole length ??? naw... unless you are planning for protection from damage. you cant jammed many romax's inside. right now i don't have the chart with me about romax size can fit in the 1 inch conduct.

what type of conduct you will plan to use ??? it can make big diffrence there .

merci , marc
Old 10-27-03, 08:48 PM
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For the tight part, I plan to use metal conduit. The rest will be plastic since more space is allowed.

I guess I hadn't thought about the romex taking up more space, but I understand why you ask. I would like to use Romax for the ease of keeping things together... but I guess I need to go with just 12 gauge non-romex.

So, revised question... how many 12-gauge wires can I 'easily' get in 1" conduit w/3 10-gauge wires already in there?

Is that better... thanks for the help.
Old 10-28-03, 07:11 AM
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How many fit is an interesting question, and one that depends on exactly what kind of wire (or cable) and what kind of conduit.

But the whole question may be moot since the ampacity derating required by putting many wires in one conduit often renders the project impractical anyway.
Old 10-28-03, 10:01 AM
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For 1" RMC the area for a 40% "fill" (3 or more conductors) is .355 sq/in. ( Chapter 9, Table 4, Art 344).

3- #10 cond. = 3 x .0333 = .0999 sq/in. = .1 sq/in
(Table 5)

.333 - .1 = .233 = area for #12 cond.

1 #12 cond = .0181 sq/in

X x .0181 = .233

X = .233/ .0181 = 12 #12 cond.

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