Calculating Ground for Overcurrent device.

[Kam1]

I was confused on a question about figuring out the grounding conductor.

It goes something like this, I don't remember the exact question, but its close to this. I just want to know how to approach this type of problem:

If there is an overcurrent device that is rated at 2100A what will the grounding conductor be?

 

[ActionDave]

That is not much to go on. Was there any more to the question that you remember?
Minimum size Equipment Grounding Conductors are found in 250.122.

 

[Kam1]

That is not much to go on. Was there any more to the question that you remember?
Minimum size Equipment Grounding Conductors are found in 250.122.

Thanks you.

So if I have to figure out the a grounding conductor and they give me the over current device is 2100A, would I just use the table on 250.122. Size up the conductor and that's how I get the ground or do I go further?

I'm sorry I don't remember the question perfectly this is all that I remember.

 

[Dennis Alwon]

If the OCPD is 2100 then the egc is required to be a 350 KCM copper conductor. As stated 250.122

 

[ActionDave]

Thanks you.

So if I have to figure out the a grounding conductor and they give me the over current device is 2100A, would I just use the table on 250.122. Size up the conductor and that's how I get the ground or do I go further?

I'm sorry I don't remember the question perfectly this is all that I remember.

If the question is that simple then yes. Sometimes the test writers will throw in a little wrinkle or some useless info to trip you up. That is why I asked if there was any more to the question.

 

[Kam1]

If the question is that simple then yes. Sometimes the test writers will throw in a little wrinkle or some useless info to trip you up. That is why I asked if there was any more to the question.

Yes you are correct, I just can't remember what else they were asking. Because I remember I got found that it was 350 kcmil during the test but I didn't know what to do next. Would you know any possible question that could be associated with a question like this? I know its very vague but this is all I remember.

 

[ActionDave]

Asking what size Al conductor is needed, while giving the correct size for Cu as one of the choices, is one.

 

[hurk27]

it will also depend on if the question is asking for the EGC size (250.122) or the GEC size (250.66) 2100 amps sounds like a service and might be a 250.66 question??
Remember bonding conductors ahead of a service is a 250.66 question.


And that is how you get tricked:rant: