Multiple panel grounding - Electrician Talk - Professional Electrical Contractors Forum

waco · 07-15-2009, 10:32 PM

Two, 200 amp residential panels, side by side. Both have GECs going to two ground rods, but only one has a ground going to the water pipe. Seems I recall that both panels have to have the primary (water pipe) ground and "daisy chaining" them (ground bar to ground bar to pipe) is a no-no.

Is my memory correct? Two grounds, one for each panel, going to the water pipe?

TOOL_5150 · 07-15-2009, 10:54 PM

One water bond is sufficient

~Matt

InPhase277 · 07-15-2009, 10:58 PM

Where do these panels get their power? I would take the ground rods and water bond to the service, not the panels.

Magnettica · 07-15-2009, 11:46 PM

I'll go one step further and say they need to go to the main disconnect.

Are these (2) 200 amp panels Main Breaker panels?

gilbequick · 07-16-2009, 07:52 AM

Are these panels a part of the same service?

waco · 07-16-2009, 08:43 AM

Sorry I wasn't clear. These are both mains with disconnects, not subs, both fed from the meter socket.

Man, if only one water pipe ground is needed, then things are good!

Dennis Alwon · 07-16-2009, 08:49 AM

Quote:

Originally Posted by waco

Sorry I wasn't clear. These are both mains with disconnects, not subs, both fed from the meter socket.

Man, if only one water pipe ground is needed, then things are good!

So there is one meter-- 400 amp service? or 2 separate meters?

waco · 07-16-2009, 08:58 AM

Quote:

Originally Posted by Dennis Alwon

So there is one meter-- 400 amp service? or 2 separate meters?

Yes, 400 amp service. You're messing with me, aren't you?

Dennis Alwon · 07-16-2009, 09:10 AM

Quote:

Originally Posted by waco

Yes, 400 amp service. You're messing with me, aren't you?

No, not really but I actually don't know for sure since I always install my gec in the meter. I believe you need both but you can jump from one panel to the other rather than run 2 separate gec's to the water pipe.

waco · 07-16-2009, 09:35 AM

Yes, I call that "daisy chaining" when going from one panel to the other then to the water pipe. Here, we don't run the GEC to the meter socket. It is my impression that it is a PUCO rule since they like to claim ownership of the meter sockets, but NEVER install them!

cmac1 · 07-16-2009, 05:54 PM

isn't the neutral conductor already providing the link.

Dennis Alwon · 07-16-2009, 07:18 PM

I think this answers the question

Quote:

250.64 Grounding Electrode Conductor Installation.

(D) Service with Multiple Disconnecting Means Enclosures. Where a service consists of more than a single enclosure as permitted in 230.71(A), grounding electrode connections shall be made in accordance with (D)(1), (D)(2), or (D)(3).
(1) Grounding Electrode Conductor Taps. Where the service is installed as permitted by 230.40, Exception No. 2, a common grounding electrode conductor and grounding electrode conductor taps shall be installed. The common grounding electrode conductor shall be sized in accordance with 250.66, based on the sum of the circular mil area of the largest ungrounded service-entrance conductor(s). Where the service-entrance conductors connect directly to a service drop or service lateral, the common grounding electrode conductor shall be sized in accordance with Table 250.66, Note 1. A tap conductor shall extend to the inside of each service disconnecting means enclosure. The grounding electrode conductor taps shall be sized in accordance with 250.66 for the largest conductor serving the individual enclosure. The tap conductors shall be connected to the common grounding electrode conductor by exothermic welding or with connectors listed as grounding and bonding equipment in such a manner that the common grounding electrode conductor remains without a splice or joint.
(2) Individual Grounding Electrode Conductors. A grounding electrode conductor shall be connected between the grounded conductor in each service equipment disconnecting means enclosure and the grounding electrode system. Each grounding electrode conductor shall be sized in accordance with 250.66 based on the service-entrance conductor(s) supplying the individual service disconnecting means.
(3) Common Location. A grounding electrode conductor shall be connected to the grounded service conductor(s) in a wireway or other accessible enclosure on the supply side of the service disconnecting means. The connection shall be made with exothermic welding or a connector listed as grounding and bonding equipment. The grounding electrode conductor shall be sized in accordance with 250.66 based on the service-entrance conductor(s) at the common location where the connection is made.