Double locknuts

[deanrdumann]

At what voltage do you you have to start using double locknuts on heavy wall pipe.

 

[iwire]

At what voltage do you you have to start using double locknuts on heavy wall pipe.

It always needs two locknuts or a locknut and a bushing not entirely of plastic.

 

[Jon456]

At what voltage do you you have to start using double locknuts on heavy wall pipe.

Unless you are using threaded hubs, how else would you secure rigid conduit to a non-threaded enclosure?

 

[RichB]

could the OP possibly mean--"double lock nuts on each side of the enclosure:jawdrop:

 

[MasterTheNEC]

Well....Mechanically speaking at any voltage you want as long as you still meet the specific requirements in Section 250.92(as iwire stated in brevity) if dealing with service conductors or Section 250.96 with bonding other enclosures. If you specifically asking "WHERE" they call this out in the NEC then I would direct you to Section 250.97 Ex.(2) which specifically gives some information for bonding over 250 volts.

 

[Knuckle Dragger]

Unless you are using threaded hubs, how else would you secure rigid conduit to a non-threaded enclosure?

Ridged set screw or compression fittings?

 

[infinity]

As Bob stated you could use one locknut on the outside and a metallic bushing on the inside.