ECN Forum Forums General Topics of the Trade General Discussion Area # of conductors in conduit

ccc = Current Carrying Conductor
See an earlier post for the definition

I know that this can be figured out using cost and labor data, but does anyone have a "rule of thumb" or equiviliant that shows when it's less expensive to go wtih another conduit or to upsize wires/consuit. ie is it better to do your homeruns with #10's in (1) 1" pipe...or run 2 3/4" pipes, etc?

As others have already said, CCC = current carrying conductor. A ground is not a CCC. A shared neutral is normally not a CCC, unless you are in a high-harmonics situation. (A shared neutral only carries the imbalance between the hots, so the total current carried by all the hots and the neutral will never be more than a full load on all the hots.)


[This message has been edited by SolarPowered (edited 02-05-2007).]

Did we ever answer the question about the 10 lamp holders, each on a snap switch and all connected to a single 20a circuit. You will have 11 current carrying conductors in the pipe but it is clear they can never overheat since total current is limited to 20a.
If anything the raceway will run cooler since 10 of them are sharing the 20a on the "hot" side.

Ah, it's times like this I'm glad I'm a PE. If the inspector doesn't like it, I stamp it, problem solved!

Please explain.

As there is no NEC exception for this IMO you have 11 CCCs minimum.

The NEC is only part of a building code.

All current national building codes allow engineering.

Any engineer can approve placing more than the NEC allowed number of conductors in a conduit.

---

That is false if your talking about raceway fill limits.

The only place the NEC allows an engineer any leeway is with conductor ampacity determination.

George that doesn't work here, if it's a violation it's tagged whether it's the installers or designers fault.

There are very few situations that would fall under "engineering supervision".

Why do you think drawings are turned down in plan review even though they are in fact sealed before they get into plan review?

A seal or stamp does not overrule code.

Roger

If this is true,why are we even required to submit engineered blueprints to plan check?

How come they get kicked back out, sometimes again and again? Do the building departments just not treat the PEs with the proper reverence that they deserve?


Bob & Roger, you beat me to it




[This message has been edited by electure (edited 02-06-2007).]