parallel conductors and grounding conductor

[ohmhead]

Question parallel conductors in multiple raceways any number any size conductor or raceway kinda a general condition .


Each raceway has a grounding conductor installed one per conduit per 250 .122

310.4 states that a phase conductor or a neutral grounded conductor can be used in parallel 1/0 and larger .
310.4 does not say or mention a grounding conductor !

250.122 f states that a grounding conductor per table 250.122 will be a full size single conductor per 250.122 C 1 in the NEC handbook article 250 page 217.
250.122 states paralleled but i see it as meaning paralleled conduits and not paralleled grounding conductors just a single GC in each paralleled conduit !

Now can you run paralleled grounding conductors in one conduit of a array of multiple parallel runs of a branch sub feeder . Meaning by example two grounding conductors in one conduit in each of the conduits in the group of multiple conduits of that paralleled feeder.

I have never seen a paralleled grounding conductors use in one single conduit ever 310.4 to me says no you cant ?

Take care

 

[chris kennedy]

Now can you run paralleled grounding conductors in one conduit of a array of multiple parallel runs of a branch sub feeder . Meaning by example two grounding conductors in one conduit in each of the conduits in the group of multiple conduits of that paralleled feeder.

Are they 1/0 or larger? Can you afford the additional lugs? Same number of conductors in all conduits?

 

[chris kennedy]

310.4 does not say or mention a grounding conductor !

The 08 is new and improved. 08 change in red.

310.4(B) Conductor Characteristics. The paralleled conductors in each phase, polarity, neutral, grounded circuit conductor, or equipment grounding conductor shall comply with all of the following:

 

[M. D.]

Excuse me for saying so,.. but they are in parallel when there is one in each .. they are each sized according to 250 .122 but they are in parallel ,.. no?

 

[chris kennedy]

they are each sized according to 250 .122 but they are in parallel ,.. no?

Why not, do they not comply with 310.4(B)(5)?

 

[iwire]

I am lost, I can't figure out what is being asked.:-?

 

[480sparky]

I am lost, I can't figure out what is being asked.:-?

If you have parallel conductors all in the same raceway, does each set of parallel conductors need their own grounding conductor?

I think.

 

[chris kennedy]

If you have parallel conductors all in the same raceway, does each set of parallel conductors need their own grounding conductor?

I think.

No, if you have parallel conduits, can you parallel the EGC in each conduit.

I think.

 

[ohmhead]

Excuse me for saying so,.. but they are in parallel when there is one in each .. they are each sized according to 250 .122 but they are in parallel ,.. no?

Well when we say paralleled we mean lets say by example three grounding conductors in one conduit or say two grounding conductors in one conduit .


We know they are in parallel as blank numbers of conduits are in say a array of multiple runs . were just asking if it can be paralleled in one single conduit.

 

[ohmhead]

No, if you have parallel conduits, can you parallel the EGC in each conduit.

I think.

Well yes Chris that is correct ! That is exactly what iam asking i dont have a 2008 code book yet ? Take care

 

[480sparky]

No, if you have parallel conduits, can you parallel the EGC in each conduit.

I think.

You must parallel a full-size (not reduced) EGC in each conduit unless the conduit is the EGC.

250.122(F) Conductors in Parallel. Where conductors are run in parallel in multiple raceways or cables as permitted in 310.4, the equipment grounding conductors, where used, shall be run in parallel in each raceway or cable.
Each parallel equipment grounding conductor shall be sized on the basis of the ampere rating of the overcurrent device protecting the circuit conductors in the raceway or cable in accordance with Table 250.122.

 

[M. D.]

I would say yes they can ,..2008 NEC

 

[ohmhead]

You must parallel a full-size (not reduced) EGC in each conduit unless the conduit is the EGC.

250.122(F) Conductors in Parallel. Where conductors are run in parallel in multiple raceways or cables as permitted in 310.4, the equipment grounding conductors, where used, shall be run in parallel in each raceway or cable.
Each parallel equipment grounding conductor shall be sized on the basis of the ampere rating of the overcurrent device protecting the circuit conductors in the raceway or cable in accordance with Table 250.122.

Well Ken that makes me think == Each parallel equipment grounding conductor key word EACH ! Has to be full sized so then we dont need to parallel ?

We now are installing a full sized grounding conductor in each raceway ?

Take care

 

[Cow]

We now are installing a full sized grounding conductor in each raceway ?

That's my take on it.

 

[480sparky]

.........We now are installing a full sized grounding conductor in each raceway ?.......

Not just now, but you should have been for years. The rule goes back to 1971.

 

[ohmhead]

Well let me see if i run a full size grounding conductor in a raceway it has to be per table 250.122 so its a full size ,


There is no need to run a parallel ground . and in the 2008 code it states in 310.4 that you can parallel a grounding conductor is that correct ?

So if we wanted to run a paralleled grounding conductor in each conduit we could but it would be a waste of material and conduit size might be a little bit larger ?

Were just asking i know this sound werd but its kinda a debate !

Take care

 

[480sparky]

310.4 just sends you to 250.122 to size the EGC. There, 250.122(F) says it must be sized according to the OCD, and each raceway must contain one.

So if you have an OCD of 2000 amps, each parallel raceway must have a 250 cu or 400 al EGC.

Here's the wording from 1971:

250.95 ...... When conductors are run in parallel in multiple raceways, as permitted in Section 310-10, the metallic equipment conductor, when used, also shall be run in parallel. Each parallel equipment grounding conductor whall be sized on the basis of the ampere rating of the overcurrent protective device protecting the circuit conductors in the raceway as per Table 250-95.

 

[Pierre C Belarge]

I believe what is being asked, is can the EGC itself be paralleled.


Let me give an example.

There is a set of parallel conductors being supplied by a 2000A overcurrent device.
Typically that would require a 250 kcmil sized EGC.

The OP wants to know could he install 2-1 AWG conductors in parallel in each raceway, instead of one 250 kcmil.

 

[480sparky]

..........The OP wants to know could he install 2-1 AWG conductors in parallel in each raceway, instead of one 250 kcmil.

Not the way I understand it. It would need a 250 in each one according to the last paragraph of 250.122(F). The first sentence would require one in each raceway.

 

[M. D.]

Well let me see if i run a full size grounding conductor in a raceway it has to be per table 250.122 so it's a full size ,

Yes.

There is no need to run a parallel ground . and in the 2008 code it states in 310.4 that you can parallel a grounding conductor is that correct ?

Yes

So if we wanted to run a paralleled grounding conductor in each conduit we could but it would be a waste of material and conduit size might be larger ?

Yes ,. again

Were just asking i know this sound werd but its kinda a debate !

Have adult beverages anything to do with this "debate":smile: