more help needed for this studying hopefull master

[jatindall82]

Needing more help. Not sure where to even start to look for this question.

A service rated 2000 amp 480v 3 phase shall have the service raceway bonded with a copper equipment grounding conductor not less than _________.

 

[infinity]

The question cannot be answered as written because certain pertinent information is missing. If you want to make assumptions start with the minimum conductor size needed for a 2000 amp service. Also there would be no EGC for bonding a service raceway it would be a boding jumper.

 

[Little Bill]

Try 250.92, 250.102(C) & Table 250.66

 

[jatindall82]

so.....

so.....

To start finding the min conductor size for a 2000 amp service, where do ii start?

 

[luckylerado]

To start finding the min conductor size for a 2000 amp service, where do ii start?

You are studying for a Masters test??

 

[iwire]

You are studying for a Masters test??

Every area is different in what they expect of journeymen, masters or may not even use those terms.

 

[jatindall82]

yes the masters

 

[lauraj]

I worked out two possible answers assuming 75C as my termination temp ratings.

5 parallel runs: 2000A/5 = 400A per conductor ===> 600kcmil
T250.102: 600kcmil x 5 = 3000kcmil equivalent area of phase conductor
3000kcmil x 0.125 (Note 1) = 375kcmil ===> 400kcmil supply-side bonding jumper

6 parallel runs: 2000/6 = 333A per conductor ===> 400kcmil
T250.102: 400kcmil x 6 = 2400kcmil equivalent area of phase conductor
2400kcmil x 0.125 (Note 1) = 300kcmil


This is assuming one single continuous conductor hitting all separate raceways.

Connecting to each single raceway with a separate SSBJ would only require a 1/0 in both scenarios.

 

[jatindall82]

check me on this one

check me on this one

Correct me if I am wrong but wouldn't I just simply look at Table 250.122and it shows for a 2000a service a 250kcmil is required?

 

[don_resqcapt19]

Correct me if I am wrong but wouldn't I just simply look at Table 250.122and it shows for a 2000a service a 250kcmil is required?

250.122 only applies on the load side of an overcurrent protective device. It does not apply to the size of service bonding jumpers. Those are sized from Table 250.102(C)(1) in the 2014 code or by Table 250.66 in previous codes.