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Grounding & Class I Location

Posted By: Dave55

Grounding & Class I Location - 12/04/04 01:01 AM

I've installed a 100-amp 1PH sub-panel next to a 200-amp 3PH main panel. This panel is about 20 feet from the meter without a disconnect on the meter socket. It's 4-wire, so the conduit is carrying the ground, but there is no grounded bushing. I'm concerned about the ground in the sub-panel, and would prefer not shutting down their operations to install the bushing.

I'm considering running a new wire outside the conduit for both panels to the building steel. There is only one driven rod outside now, and only for the meter socket. Any suggestions?

Also there is a paint-mixing room with flamable liquids, and the door is always open. Wouldn't this make the room next to it Class I also? By the way, this is the room with the panel and sub-panel.


Posted By: George Little

Re: Grounding & Class I Location - 12/04/04 05:02 PM

IMHO - If the 3 phase panel was installed to code, meaning #1 The conduit was was bonded on one end and the other end at least had a regular bushing on it. #2 The bonding screw was installed, bonding the grounded conductor to the panel. #3 The GEC was run to the Grounding Electrode per 250.24. I don't think I'd be worried about the equipment ground beyond that point standard grounding for a 120/240v system is adaquate. I read that that you have a 20' run of conduit from the meter to the 3 phase panel- could be an issue of location per 230.70(A). I assumed your 100a. new panel would be a sub off the 200a. As to the Class I area, sounds like someone needs to classify the area and provide documentation per 500.4(A) before we get concerned.

[This message has been edited by George Little (edited 12-04-2004).]

[This message has been edited by George Little (edited 12-04-2004).]
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