Two Panels/ One Raceway

[Pepper44]

Hello,

This is my first inquiry on your site and would like your opinions on a grounding issue that doesn't seem to be clearly defined by the NEC or our AHJ.
We have two seperate (same source MSB) 120/208 3P/4W panelboards feeding 3P/208V rectifiers (no neutral) through a single 2" EMT conduit (via a j box). What are your thoughts on the grounding conductors required in this conduit? I am arguing for one but the inspector indicated there should be grounding from each source panel.

Thanks for your time.

 

[augie47]

Perhaps arguable, but I would say 300.3(B) would require two, one from each panel.

 

[Pepper44]

Perhaps arguable, but I would say 300.3(B) would require two, one from each panel.

Thanks Augie, I appreciate the feedback.

 

[hillbilly1]

Hello,

This is my first inquiry on your site and would like your opinions on a grounding issue that doesn't seem to be clearly defined by the NEC or our AHJ.
We have two seperate (same source MSB) 120/208 3P/4W panelboards feeding 3P/208V rectifiers (no neutral) through a single 2" EMT conduit (via a j box). What are your thoughts on the grounding conductors required in this conduit? I am arguing for one but the inspector indicated there should be grounding from each source panel.

Thanks for your time.

Perhaps arguable, but I would say 300.3(B) would require two, one from each panel.

Do you mean taking the sole EGC to one panel only? Or splitting it in the j-box? As long as it is sized for the largest OCP, I think 300.3(B) would be met unless you are taking it to one panel only.

 

[Pepper44]

Yes, since branch circuits initiate at both panelboards (in this case 50/3 OCP) and share one raceway after the J box we were uncertain of the grounding requirements. Seems like one would fulfill the raceway grounding since they are from the same source MSB (not seperately-derived systems).

 

[hillbilly1]

Yes, since branch circuits initiate at both panelboards (in this case 50/3 OCP) and share one raceway after the J box we were uncertain of the grounding requirements. Seems like one would fulfill the raceway grounding since they are from the same source MSB (not seperately-derived systems).

So this is on the load side of the panel boards? I thought you were talking about the feed to the panels theirselves, I think it still would meet article 300 if both EGC's are terminated together at the j-box, (also bonding the box) then a single EGC ran from that point.

 

[Smart $]

So this is on the load side of the panel boards? I thought you were talking about the feed to the panels theirselves, I think it still would meet article 300 if both EGC's are terminated together at the j-box, (also bonding the box) then a single EGC ran from that point.

I agree. Wherever the conductors are in the same conduit, one EGC satisfies the requirements, but between originating panelboard and that conduit, an individual EGC must be run along with circuit conductors to the originating panelboard.

 

[Pepper44]

I agree. Wherever the conductors are in the same conduit, one EGC satisfies the requirements, but between originating panelboard and that conduit, an individual EGC must be run along with circuit conductors to the originating panelboard.

Thanks for the feedback guys, we're going to run two EGC's (one from each panelboard).