GEC needed?

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kbsparky

kbsparky

Senior Member
Location
Delmarva, USA
I have an insteresting scenerio on a job we are about to start:

On an existing property, a new warehouse is being built. It will be supplied by an underground 5-wire feeder from the main building, delta 3 phase, 120/240 Volts. We will keep the EGC separated from the neutral, since there will be phone and computer lines connected between the buildings, and we want to eliminate the possibility of parallel paths of returning current flow.

The main service panel enclosure will be bolted directly to "building steel"

So, the underlying question is:

Will we have to install a grounding electrode conductor from the enclosure of the panel to the building steel? If so, why? The panel is already solidly bolted to the steel ...
 
benaround said:
...try 250.32 it has all the answers for your situation.
Click to expand...
OK, let's elaborate on this.

250.32 (b)(1) describes our situation, with an equipment grounding conductor run from the main building to the warehouse. The conductors will be installed in underground PVC conduit, which we trenched and installed just today.

Now, in that paragraph of the Code it plainly states "An equipment grounding conductor as described in Section 250.118 shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be bonded...

Looking up the cross-reference in section 250-118 we find that the equipment grounding conductors shall be one or more of a combination of the following:

(1) A copper ... conductor.
(14) Other electrically continuous metal raceways listed for grounding.

I submit that the enclosure of the listed panelboard satisfies such requirements, as the grounding bar is bolted to the back of the enclosure. The enclosure in turn is bolted to the building steel. I also submit that the bolts that come with the ground bar kit are steel, and are not copper or aluminum as someone here has suggested.
 
kbsparky,

Is this beam the only GE in the building?? Also, does it qualify as a GE per

250.52(2) (or) if you have other GE's that you are using that terminate on

the EGbar then IMO your 'building steel' ,as you described it, should work just

fine.

Are you being told that it has to be in a 'conductor' form??
 
benaround said:
....
Are you being told that it has to be in a 'conductor' form??
Click to expand...

Only in here has that suggestion been made. I asked my local inspector-critter after posting this, and he said that the intent of the Code is well satisfied by bolting the panel to the steel purlons, and no other "conductor" would be necessary to achieve the required bonding.

Now, if there were steel or wooden studs involved, or some other means of supporting that panel, then a GEC would be necessary and proper.
 
kbsparky,

If other GE's are available they all bond together to form the GES and land

on the EGbar,but the 'steel' is already done.

Well it's allways a good feeling to discuss things with the Inspector before

the work is completed, Have a good one tomorrow!
 
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