Wiring and Roughing-in Works

[Fel Flores]

Good day.

Will there be a code violation if I will be wiring several branch circuits in one conduit? The conduit will be sized properly in accordance with Table C.4 to accommodate all the wires and each branch circuit will have its own disconnecting means.

Thank you!

 

[Smart $]

Running several branch circuits in one conduit is quite common and completely compliant.

 

[infinity]

Also take a look at 310.15(B)(3).

 

[Fel Flores]

Running several branch circuits in one conduit is quite common and completely compliant.

Is it real in actual installation though? Thank you!

 

[JFletcher]

Is it real in actual installation though? Thank you!

Yes, very real. Especially where numerous circuits are going to roughly the same place. It's faster, easier and cheaper to run fewer conduits with multiple circuits than one conduit per circuit.

 

[Fel Flores]

I mean, the "degradation" of the ampacities of wires Is it true in actual installation?

 

[user 100]

I mean, the "degradation" of the ampacities of wires Is it true in actual installation?

Do you actually mean derating?

Are you concerned about a lessened ability of the insulation of the wiring itself when ckts are grouped in conduit?

 

[Fulthrotl]

I mean, the "degradation" of the ampacities of wires Is it true in actual installation?

circuits are derated to prevent overheating in crowded conduits.
there is a schedule to tell you how much to derate. depends on
the number of ungrounded conductors in the raceway.

 

[GoldDigger]

circuits are derated to prevent overheating in crowded conduits.
there is a schedule to tell you how much to derate. depends on
the number of ungrounded conductors in the raceway.

Sometimes, particularly with branch circuits, the grounded conductors are counted too

Sent from my XT1585 using Tapatalk

 

[petersonra]

I mean, the "degradation" of the ampacities of wires Is it true in actual installation?

It is rare that the full ampacity of all the conductors is actually used. The heating effects are I^2R so as the current is reduced the heat generated is reduced by a factor of the ratio of the squares so even a relatively small reduction in current results in a big chunk of heat that is not produced.

But the code gives you no credit for this kind of thing except in article 725.