Residential Service w/two ground rods?

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scrino

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I have recently seen an electrical installation where a new single family home has a 400a 120/240v 1 ph service. The electrican installed a 400a meter base, then parallel conductors from the meter to two (2) 200a MCB panelboards. From each 200a MCB panel, there was a GEC to an exterior driven gound rod. Also there was no bond between each 200a panelboard.

Any idea where in the NEC this installation is discussed? Is this install acceptable?

My understanding was only one GEC and GES are allowed except in a separately derived system.

I believe the electrician also installed a driven ground rod at the exterior water well. BTW all was inspected and approved by the local electrical inspector.

Thanks for any feedback.
 
Re: Residential Service w/two ground rods?

250.24(A)(1) States that the actual connection of the grounded service conductor can be made at various locations.

Does this mean any, both or all connection locations can be installed? Which is why im confused in seeing the multiple ground rods with no bond between them.
 
Re: Residential Service w/two ground rods?

What about 250.50?
All grounding electrodes . . . shall be bonded together to form the grounding electrode system.
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Re: Residential Service w/two ground rods?

Would they bond together at the meter with this installation?

In other words from each panel through the grounded (neutral) back to the meter thus bonding together.
:confused:
 
Re: Residential Service w/two ground rods?

Originally posted by scrino:


I believe the electrician also installed a driven ground rod at the exterior water well. BTW all was inspected and approved by the local electrical inspector.
Click to expand...
yeh..but whats going on here, where is the path?

Am I missing something? :confused: *Is it the earth?

[ September 26, 2005, 01:57 PM: Message edited by: dillon3c ]
 
Re: Residential Service w/two ground rods?

I have found 250.58 which if I understand correctly, you are allowed to have multiple ground rods IF they are bonded together to be considered a single grounding electrode.

So now I guess what is considered "bonded" grounding electrodes?

-a GEC clamped to each below the earth?
-neutrals grounded back at the meter base?
 
Re: Residential Service w/two ground rods?

Thanks Charlie B. The first sentence in 250.50 basically clarifies. Just had to read it a little slower.
 
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