EGC--------Quiz

[ibew441dc]

6000 OCPD feeding a 3 phase load
Raceway is PVC

1)Using 16 parallel sets of 500 kcmil
What size EGC is required in each raceway?

2)Using 15 parallel sets of 600 kcmil
What size EGC is required in each raceway?

3)Using 40 parallel sets of 1/0
What size is required in each raceway?

 

[iwire]

Dan did you mean to use 500 kcmil twice or should #2 be 600?

 

[ibew441dc]

Dan did you mean to use 500 kcmil twice or should #2 be 600?

oops!:wink: thanks:smile: i fixed it.

 

[Pierre C Belarge]

6000 OCPD feeding a 3 phase load
Raceway is PVC

1)Using 16 parallel sets of 500 kcmil
What size EGC is required in each raceway? 500kcmil -250.122

2)Using 15 parallel sets of 500 kcmil
What size EGC is required in each raceway? Not permitted-
3)Using 40 parallel sets of 1/0
What size is required in each raceway?

Not realistic

 

[ibew441dc]

Not realistic

gimme an answer....so what if its make believe.....crunch the numbers:grin:

 

[Pierre C Belarge]

The site keeps adjusting my answer

1. 500 kcmil

2. (you changed to 600Kcmil) 600kcmil

3. Unrealistic - 1/0

All based on the first paragraph of 250.122 and 250.122((F)((1)

 

[don_resqcapt19]

In all cases the EGC must be 800 kcmil copper.

 

[ibew441dc]

In all cases the EGC must be 800 kcmil copper.

And the Winner is don_resqcapt19!!!!

 

[Pierre C Belarge]

Read the first paragraph of .122


It does not make sense to have the equipment ground conductor larger than the phase conductor, as the phase conductor will be limited by it's size in regards to the ampacity. Hence, the first paragraph of .122.

 

[iwire]

In all cases the EGC must be 800 kcmil copper.

I was thinking 250.122(B) may change that answer.

I was starting to work the numbers but now wonder if you already did.

 

[ibew441dc]

Read the first paragraph of .122


It does not make sense to have the equipment ground conductor larger than the phase conductor, as the phase conductor will be limited by it's size in regards to the ampacity. Hence, the first paragraph of .122.

A lot of things in the NEC don't make sense.......read 250.122(F):smile:

 

[Pierre C Belarge]

A lot of things in the NEC don't make sense.......read 250.122(F):smile:

Look at my post of 8:21pm


did you read the first paragraph of .122

250.122(A)General.
Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wir type shall not be smaller than shown in Table 250.122 BUT SHALL NOT BE REQUIRED TO BE LARGER THAN THE CIRCUIT CONDUCTORS supplying the equipment.

 

[SEO]

Min size of equipment grounding conductor per table 250.122 for a 6000 amp overcurrent device is an 800 kcmil cu. for conductors in parallel section 250.122 (F) requires the equipment grounding conductor in each conduit to be sized per the overcurrent device.

 

[Pierre C Belarge]

Min size of equipment grounding conductor per table 250.122 for a 6000 amp overcurrent device is an 800 kcmil cu. for conductors in parallel section 250.122 (F) requires the equipment grounding conductor in each conduit to be sized per the overcurrent device. unless the equipment ground conductor would be larger than the phase conductors. The equipment ground conductor is not required to be larger than the phase conductor as per 250.122(A):grin:

................

 

[don_resqcapt19]

Look at my post of 8:21pm


did you read the first paragraph of .122

250.122(A)General.
Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wir type shall not be smaller than shown in Table 250.122 BUT SHALL NOT BE REQUIRED TO BE LARGER THAN THE CIRCUIT CONDUCTORS supplying the equipment.

The circuit conductor is not the conductor in each raceway...it all of the individual conductors that are connected in parallel. The code requires a 800 kcmil in each raceway, no matter how big or small the individual conductors that make up the circuit conductor are.

 

[don_resqcapt19]

I was thinking 250.122(B) may change that answer.

I was starting to work the numbers but now wonder if you already did.

I never even looked at that section. However now that I did look, it does not apply. The conductors are not oversized.

 

[iwire]

The conductors are not oversized.

No?

#3 is 6000 amps exactly, the other two examples are over. As always the question is what size is the normal size?

 

[SEO]

It doesn't matter how many conductors you have the equipment grounding conductor is sized per the overcurrent device.

 

[don_resqcapt19]

No?

#3 is 6000 amps exactly, the other two examples are over. As always the question is what size is the normal size?

If you took one set out of the other two, they would be undersized, so I would call them normal size.

 

[iwire]

If you took one set out of the other two, they would be undersized, so I would call them normal size.

I'll buy that, I just had assumed that was where Dan was heading with this quiz. :smile: