bonding bushings required

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wireman1

wireman1

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does 2 in. rigid pipe or emt pipe leaving a main service center to feed a 2ooamp 480/277 3 phase panel need bonding bushings on each end cite code articles thank you
 
If concentric or eccentric ko's are used it depends on listing of the enclosure with such ko's. otherwise if listed for purpose or a same size opening as the raceway no additional bonding methods are required. See 250.97
 
kwired said:
If concentric or eccentric ko's are used it depends on listing of the enclosure with such ko's. otherwise if listed for purpose or a same size opening as the raceway no additional bonding methods are required. See 250.97
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If I remember correctly the exclusion of the bonding jumper for items listed for bonding over 250 volt to ground only applies to boxes. It would not apply to a disconnect switch or a panel enclosure, etc.
 
infinity said:
If I remember correctly the exclusion of the bonding jumper for items listed for bonding over 250 volt to ground only applies to boxes. It would not apply to a disconnect switch or a panel enclosure, etc.
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Copied from 2014 NEC:

"Exception: Where oversized, concentric, or eccentric knockouts are not encountered, or where a box or enclosure with concentric or eccentric knockouts is listed to provide a reliable bonding connection, the following methods shall be permitted:"
 
kwired said:
Copied from 2014 NEC:

"Exception: Where oversized, concentric, or eccentric knockouts are not encountered, or where a box or enclosure with concentric or eccentric knockouts is listed to provide a reliable bonding connection, the following methods shall be permitted:"
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I think the ko's typically found on meter sockets are the heavier duty type listed for grounding over 250, but I have never dug into the paperwork to confirm.
 
electrofelon said:
I think the ko's typically found on meter sockets are the heavier duty type listed for grounding over 250, but I have never dug into the paperwork to confirm.
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Do you have any examples of what to look for on a datasheet, to determine if the ring KO's are rated for 250V-600V bonding? Not necessarily for a meter socket, just in general.
 
As far as I know only the smaller boxes have the KOs listed for grounding with some of the rings remaining. I don't think any cabinet for a panelboard or enclosure for a disconnect are so listed. One of the issues may be the thickness of the material. The larger enclosures are often not thick enough to engage two threads of a screw with a 32 thread per inch pitch, but the 4 square boxes are.
 
Unlike a "loadcenter" most panelboards I've run into you need to drill your own holes anyway. Some might have KO's on one end but not the other, all you need to do is turn it the other way if you have everything coming out of one end, the interior usually fits either way.

Most of the ones I have been using were outdoors N12/3R (remove some drain screws to convert to 3R) - so definitely no ko's in top. Bottom of the ones I've been using have no KO's either.
 
electrofelon said:
I think the ko's typically found on meter sockets are the heavier duty type listed for grounding over 250, but I have never dug into the paperwork to confirm.
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Would they even need to be? A raceway with SEC's would still require a bonding bushing regardless of the listing of the meter enclosure with concentric or eccentric KO's.
 
Actually metallic service raceway does not require a bonding bushing, just requires something other than a standard locknut to assure better bond.

I don't believe it needs to be on both ends either, just one bond to the raceway that is other than standard locknuts.
 
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