Multiple Sub-panels and grounding rods, and ground wire

[dcg9381]

Double checking this.
I have a service entrance (bonded neutral/ground) panel that then feeds what are essentially 3 sub-panels (sub panel, ATS, sub-panel-load-center) on a separate structure. All 3 of these panels are in close proximity and on the same structure.

That structure has a ground rod/rod(s) (it's actually tied into the foundation steel).

I want to confirm that all 3 of my sub panels should have grounds interconnected and can utilize that same ground rod configuration. Also looking to confirm what AWG ground wire should be used here for 200A service.

I have a master electrician employed, but it's easier to get this sorted out with you guys in advance. I'm setting 2 of these panels for him and interconnecting them in advance.

 

[sberry]

Number 6 for 200 between panels and 4 to footer steel. If you have footer steel you dont need the other rods. Whoops, I see second panels in another structure, need rods there or to footer steel.
For the purpose of this discussion,,, the rods are to hopefully carry lightening strike to ground vs having the ground wire carry it back to the first structure.

 

[wyliesdiesels]

Double checking this.
I have a service entrance (bonded neutral/ground) panel that then feeds what are essentially 3 sub-panels (sub panel, ATS, sub-panel-load-center) on a separate structure. All 3 of these panels are in close proximity and on the same structure.

That structure has a ground rod/rod(s) (it's actually tied into the foundation steel).

I want to confirm that all 3 of my sub panels should have grounds interconnected and can utilize that same ground rod configuration. Also looking to confirm what AWG ground wire should be used here for 200A service.

I have a master electrician employed, but it's easier to get this sorted out with you guys in advance. I'm setting 2 of these panels for him and interconnecting them in advance.

those arent called ground rods if its in the footing. Its called a UFER

As to the panels needing a connecting to a grounding electrode. only the first panel in a structure needs to be connected to TWO grounding electrodes. The rest just connect via the EGC. a generator does not need a grounding electrode.

So in your picture, the panel on the left needs 2 ground rods and the first panel on the right needs 2 ground rods. the generator does not

 

[dcg9381]

So in your picture, the panel on the left needs 2 ground rods and the first panel on the right needs 2 ground rods. the generator does not

Thanks Wylie!

Interesting that the POC passed that left panel (there are actually 2) and the ground rod (singular) was done per their specification. It uses a 3/4" rod that's 10' deep. They're very particular and don't allow deviations. I've attached that spec if you're curious. Those panels are also done in metal conduit with connecting rings that contain ground wires, dunno if that matters.


The residential structure is UFER ground - thanks for the naming convention. Sounds like I can connect both the sub-panel and the ATS through to the load panel via #6 and let the electrician handle grounding of that panel to the UFER via #4.

It looks like the generator, with no switched neutral isn't a "separately derived system" and can be ground through to the other panels. It's prior install, there was no ground wire to the ATS, I suppose that's why they grounded it separately.

Really appreciate the help!

 

[wyliesdiesels]

Thanks Wylie!

Interesting that the POC passed that left panel (there are actually 2) and the ground rod (singular) was done per their specification. It uses a 3/4" rod that's 10' deep. They're very particular and don't allow deviations. I've attached that spec if you're curious. Those panels are also done in metal conduit with connecting rings that contain ground wires, dunno if that matters.


The residential structure is UFER ground - thanks for the naming convention. Sounds like I can connect both the sub-panel and the ATS through to the load panel via #6 and let the electrician handle grounding of that panel to the UFER via #4.

It looks like the generator, with no switched neutral isn't a "separately derived system" and can be ground through to the other panels. It's prior install, there was no ground wire to the ATS, I suppose that's why they grounded it separately.

Really appreciate the help!

metal conduit and EGCs have nothing to do with grounding electrodes. they are not the same animal. And there shouldnt be EGCs between the main panels and the meter socket. Its not necessary.

 

[Shovelhead]

Double checking this.
I have a service entrance (bonded neutral/ground) panel that then feeds what are essentially 3 sub-panels (sub panel, ATS, sub-panel-load-center) on a separate structure. All 3 of these panels are in close proximity and on the same structure.

What is the function of sub panel 1 ?
What does that panel contain?

Thanks

 

[dcg9381]

What is the function of sub panel 1 ?
What does that panel contain?

Thanks

It's a panel that is used for a future solar array. It has to be upstream of the generator ATS - otherwise it's possible for a solar array to back-feed the generator. It's essentially non-generator-protected power input/output.