does GB count as a lock nut

[Ponchik]

Sometimes the threads of a fitting are not long enough to accommodate the lock nut and the grounding bushing. In this case is it allowed to leave out the lock nut and just install the grounding bushing? Basically the GB acts like a lock nut and as a grounding bushing.

 

[infinity]

I would say no. The fitting is listed and tested with a locknut. A metal bushing and one locknut on RMC would be a different story.

 

[Ponchik]

I would say no. The fitting is listed and tested with a locknut. A metal bushing and one locknut on RMC would be a different story.

What is a metal bushing?

 

[guschash]

Bushing that's metal, we used them all in the Industial plant I working. Had to it was so hot plastic would melt.

 

[kwired]

Bushing that's metal, we used them all in the Industial plant I working. Had to it was so hot plastic would melt.

What kind of conductors did you run? Most plastic bushings are rated 90C or even 105C.

 

[480sparky]

What is a metal bushing?

 

[kwired]

What is a metal bushing?

I can't tell if it is metal or not. Kind of feels like the rest of my computer screen:lol:

 

[Ponchik]

If metal bushing can be used as a lock nut then whats the difference between the metal bushing and the grounding bushing? besides one has an
attachment for the grounding wire.

 

[480sparky]

I can't tell if it is metal or not. Kind of feels like the rest of my computer screen:lol:

Try hitting it with a 3-lb sledge. :happyyes:

 

[iwire]

I only have a second but somewhere there is a code section that says that bushing made solely of insulating material shall not be used in place of a locknut' That leads me to believe a metal bushing could be used in place of a locknut and I see it often in old buildings around Boston.

 

[Ponchik]

I only have a second but somewhere there is a code section that says that bushing made solely of insulating material shall not be used in place of a locknut' That leads me to believe a metal bushing could be used in place of a locknut and I see it often in old buildings around Boston.

A grounding bushing is not made of an insulation material. But is it a code issue or a UL listing issue?

 

[infinity]

I only have a second but somewhere there is a code section that says that bushing made solely of insulating material shall not be used in place of a locknut' That leads me to believe a metal bushing could be used in place of a locknut and I see it often in old buildings around Boston.

I agree, very common in older buildings. Once your conductors get to #4 or larger the bushing can no longer be solely made of metal as it's required to be insulating.

 

[kwired]

Try hitting it with a 3-lb sledge. :happyyes:

I only have an 8-lb sledge, should I still try with that?

 

[jusme123]

I only have a second but somewhere there is a code section that says that bushing made solely of insulating material shall not be used in place of a locknut' That leads me to believe a metal bushing could be used in place of a locknut and I see it often in old buildings around Boston.

300.4(G)

 

[guschash]

We had to use all fiberglass conductors, the temperatures ran from 2000 down to 185 when the glass was be cut. So hot we could work only 10 to 15 minutes in the heat. We had to use porcelain connectors,plastic would melt.