# Chase nipple!



## Lateatnyte (Dec 10, 2013)

I am installing overhead aluminum tray in a data center. Many 1200-4000 amp 416 volt feeders. The tray turns down into switchgear where we are punching 3 inch holes and installing chase nipples. I was questioned about the need for grounding bushings. I believe they would only be needed if the nipple was in a concentric knockout or if for a service. Am I missing something ?


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## Bkessler (Feb 14, 2007)

As far as I know your correct.


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## Chrisibew440 (Sep 13, 2013)

Lateatnyte said:


> I am installing overhead aluminum tray in a data center. Many 1200-4000 amp 416 volt feeders. The tray turns down into switchgear where we are punching 3 inch holes and installing chase nipples. I was questioned about the need for grounding bushings. I believe they would only be needed if the nipple was in a concentric knockout or if for a service. Am I missing something ?


You need to bond the tray to the nipple with a bond bushing.


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## CADPoint (Jul 5, 2007)

How do you get pass *250.96*, *250.97*, *250.98*, *250.100* (if appliable) or *250.102(C)*, use plastic.


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## Lateatnyte (Dec 10, 2013)

I am bringing a separate grounding wire up from switchgear grounding bar and using a compression lug to bond the tray. My interpretation of 250.97 would be the application falls under exception #3. It is not a service so how is it different than EMT which would not require the grounding bushing?


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