Bonding bushings

[Michiganelectrix98]

I am getting mixed reviews between co workers…. Where are binding bushings required exactly? Does it depend on the knockout? Voltage? Piece of equipment?
Also where are plastic bushings required?

 

[Dennis Alwon]

It does depend on voltage and the type of ko. Section 250.94 is where you can start, or you can tell us the application, voltage etc

 

[infinity]

Above 250 volts to ground {250.97} and below 250 volts to ground have different requirements where concentric or eccentric KO's are involved. Plastic bushing aren't technically required anywhere but they may be used when meeting the requirements of 300.5(H).

 

[NTesla76]

There is a flow chart around here somewhere that is pretty handy.

 

[augie47]

 

[infinity]

 

[Michiganelectrix98]

Drilling into a disconnect. 480v. Rigid conduit to meyers hub no knockouts. Fed from 480v panel. Then load side of disconnect rigid nipple to sealtite into a charger.

 

[Michiganelectrix98]

It does depend on voltage and the type of ko. Section 250.94 is where you can start, or you can tell us the application, voltage etc

I just updated the thread thanks please look

 

[infinity]

480v. Rigid conduit to meyers hub no knockouts.

If there are no concentric or eccentric KO's (which you've stated that there are none) no bonding bushing required for the Myers hub.

Then load side of disconnect rigid nipple to sealtite into a charger.

If there are no concentric or eccentric KO's associated with the rigid nipple then no bonding bushing required there either.

 

[herding_cats]

follow the flowchart. It all depends on the conduit and raceway, etc.

 

[Ponchik]

FWIW, this is from the 2015 UL book:





CONCENTRIC OR ECCENTRIC KNOCKOUTS

All boxes with concentric or eccentric knockouts have been investigated for bonding and are suitable for bonding without any additional bonding means around concentric (or eccentric) knockouts where used in circuits above or below 250 V, and may be marked as such.

 

[infinity]

FWIW, this is from the 2015 UL book:





CONCENTRIC OR ECCENTRIC KNOCKOUTS

All boxes with concentric or eccentric knockouts have been investigated for bonding and are suitable for bonding without any additional bonding means around concentric (or eccentric) knockouts where used in circuits above or below 250 V, and may be marked as such.

Yes for boxes nothing else is required. This wouldn't apply to a disconnect switch.

 

[Ponchik]

Yes for boxes nothing else is required. This wouldn't apply to a disconnect switch.

By disconnect, you mean service disconnect, correct?

 

[infinity]

By disconnect, you mean service disconnect, correct?

Any disconnect switch with concentric or eccentric KO's. Unlike boxes those are not listed for bonding when the voltage is over 250 volts to ground.

 

[tortuga]

You guys should update that flow chart, there is a corrected version that shows a metallic raceway always needs a bond bushing when it enters a non-metallic enclosure 314.3 Exception No1. regardless if the enclosure on the other end is metal or not.

 

[Ponchik]

Any disconnect switch with concentric or eccentric KO's. Unlike boxes those are not listed for bonding when the voltage is over 250 volts to ground.

what is the code section?

ETA, I think I found it 250.97 that refers back to 250.92(B)

 

[tortuga]

I found the corrected flow chart