grounding electrode conductor taps

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buck33k

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Washington state and North Carolina
250.64(D) says it shall be permitted to connect taps from each service panel to a common grounding electrode conductor as illustrated in the handbook.
I'm assuming the common grounding electrode conductor isn't necessary if the taps go directly to building steel. Am I correct?
Sizing of the taps would be based on 250.66 per the service conductors feeding each panel.
Thanks
Buck
 
Re: grounding electrode conductor taps

I don't agree with your assumption in that the building steel is not the GEC, it is only the GE.

[ January 17, 2006, 12:27 PM: Message edited by: bphgravity ]
 
Re: grounding electrode conductor taps

Thanks Bryan,
So it would be necessary to have the common grounding electrode conductor even if it we're only 6" long?
In this case the taps would split bolt to the short common GEC which would be attached to building steel.
My example is a little extreme but I just want to make sure this is necessary.
 
Re: grounding electrode conductor taps

Bryan
I think that Buck is reading the last sentence in .58 and is thinking if he runs his GECs to the steel, that he is good to go. As the steel effectively bonds all of the separate GECs to become one.
 
Re: grounding electrode conductor taps

I may be wrong, but I think the common grounding electrode conductor serving the taps is for a matter of convenience but not required as it may seem in 250.64(D).
If two service panels were adjacent to a building steel column, it would seem impracticle not to simply connect the individual GECs to the electrode(bldg steel).
250.64 doesn't say you can do this but it doesn't say you can't.
Since my last post I have referred to Soares and found the following comment, "If the installer choses to, an individual GEC may be installed from each service disconnecting means enclosure to the grounding electrode. In this case, the GEC is sized for the service entrance conductor serving that enclosure."
I greatly appreciate the input.
Buck

[ January 17, 2006, 09:03 PM: Message edited by: buck33k ]
 
Re: grounding electrode conductor taps

As a side note, 250.52(A)(2) lays out what it means for building steel to be considered effectively grounded and therefore subject to being utilized as a grounding electrode. It has been my experience that more often than not, the building steel does not qualify as being suitable for use as a grounding electrode.
 
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