Parallel Sets Ground Size

[Fitzdrew516]

Almost positive I got this one right, but since it's such a big item I want to make sure I am. I am feeding a new 3000A service with (8) sets of 500kCMIL copper. I'm getting that I need to run a 1/0 ground in each set. Correct?

Thanks,
-Drew

 

[Carultch]

Almost positive I got this one right, but since it's such a big item I want to make sure I am. I am feeding a new 3000A service with (8) sets of 500kCMIL copper. I'm getting that I need to run a 1/0 ground in each set. Correct?

Thanks,
-Drew

It's 1 full size EGC in each conduit or other raceway/wire structure. Not necessarily each parallel set, but rather each conduit.

If you group two sets in one conduit, you only need 1 egc between the two sets, and thus 4 egc's total. Unlikely that you'd be paralleling two sets of 500 kcmil in the same conduit, but it could happen in other examples.
If you put each set in its own conduit, then you'll need 8 egc's total.

 

[infinity]

If these are service entrance conductors with a neutral you do not need any EGC's.

 

[luckylerado]

...1/0 ground in each set. Correct?

I disagree

 

[iwire]

Almost positive I got this one right, but since it's such a big item I want to make sure I am. I am feeding a new 3000A service with (8) sets of 500kCMIL copper. I'm getting that I need to run a 1/0 ground in each set. Correct?

Thanks,
-Drew

Is it really a service or is it a feeder?

If it is a service do you run an EGC?

 

[Fitzdrew516]

It is most definitely a service (from the utility transformer to building) and to clear up any confusion I will be running each set in it's own conduit.

 

[Fitzdrew516]

If these are service entrance conductors with a neutral you do not need any EGC's.

4-wire service, you are correct about that. I've always run a ground for a 4-wire service. I'm a bit confused as to why you wouldn't have to.

 

[iwire]

It is most definitely a service (from the utility transformer to building) and to clear up any confusion I will be running each set in it's own conduit.

No EGCs at all then.

 

[iwire]

4-wire service, you are correct about that. I've always run a ground for a 4-wire service. I'm a bit confused as to why you wouldn't have to.

You would run a grounded conductor for a service not an EGC.

If you have run EGCs for a service they were either left floating at the power company end or they became parallel neutral conductors.

Remember, the neutral is bonded at the utility transformer and at the service disconnect, what would an EGC for us?

 

[Fitzdrew516]

You would run a grounded conductor for a service not an EGC.

If you have run EGCs for a service they were either left floating at the power company end or they became parallel neutral conductors.

Remember, the neutral is bonded at the utility transformer and at the service disconnect, what would an EGC for us?

Wow, well... my mind is blown and kind of hurts now. :huh: Can you think of any benefits to running the ground and leaving it floating? Future use for any reason?

 

[iwire]

Can you think of any benefits to running the ground and leaving it floating? Future use for any reason?

No, none at all that I know of.

Just some power companies will not land it because they know it is not needed.

Consider this, is there an EGC between your home and the utility transformer supplying it?

Even though the service is larger and has an extra ungrounded conductor the rules are the same.

 

[ADub]

Wow, well... my mind is blown and kind of hurts now. :huh: Can you think of any benefits to running the ground and leaving it floating? Future use for any reason?

Probably not. Especially if it's green. Is this how you've been doing services? If so did you just land them on the neutral assembly?

 

[Fitzdrew516]

No, none at all that I know of.

Just some power companies will not land it because they know it is not needed.

Consider this, is there an EGC between your home and the utility transformer supplying it?

Even though the service is larger and has an extra ungrounded conductor the rules are the same.

I'm in a predicament. Everything you're saying makes sense, but the years of me running this unnecessary conductor screams WARNING. Haha. I know, I know.... the "because we've always done it that way" excuse is dumb, but it seems to be the only thing left for me to hold on to at this point, lol.

 

[Fitzdrew516]

Probably not. Especially if it's green. Is this how you've been doing services? If so did you just land them on the neutral assembly?

I'm referring to specifying it. At the first engineering firm I worked for (started as a co-op and got hired on when I graduated) that's just how I was told to do it and I never questioned it. Now I'm questioning everything. My whole life is a lie. :lol:

 

[ADub]

I'm referring to specifying it. At the first engineering firm I worked for (started as a co-op and got hired on when I graduated) that's just how I was told to do it and I never questioned it. Now I'm questioning everything. My whole life is a lie. :lol:

Haha I understand. Seems weird it went so long unchecked. Honestly if it ever showed up on a spec of mine i would have it corrected or at least acknowledged as unnecessary.

 

[iwire]

Haha I understand. Seems weird it went so long unchecked. Honestly if it ever showed up on a spec of mine i would have it corrected or at least acknowledged as unnecessary.

I think most ECs would ignore it and pocket the money.

 

[ADub]

Parallel Sets Ground Size

I think most ECs would ignore it and pocket the money.

Sounds about right