Do all raintight connectors need bond bushings?

[Oishrock]

Do all raintight connectors need bond bushings? My buddy and I have been having a debate about Emt raintight connectors and whether they meet the definition of being bonded. The NEC 250.97 Bonding for Over 250 Volts For circuits of over 250 volts to ground, the electrical continuity of metal raceways and cables with metal sheaths that contain any conductor other than service conductors shall be ensured by one or more of the methods specified for services in 250.92(B), except for (B)(1). 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 areliable bonding connection, the following methods shall be permitted: (3) Fittings with shoulders that seat firmly against the box or cabinet, such as electrical metallic tubing connectors, flexible metal conduit connectors, and cable connectors, with one locknut on the inside of boxes and cabinets. The problem is the shoulder with a raintight connector doesn't fit against the box/cabinet due to the gasket/washer that is supposed to make it raintight.

 

[FREEBALL]

Would not the fact that the locknut is threaded to the connector and made metal contact to the inside of the enclosure be enough, provided we are talking nonconcentric/eccentric KO. Some locknuts are made to dig in to the cabinet finish but if not the area around the inside of the cabinet could have finish removed so locknut can make a firm metal bond. I use the bonding locknuts with the screw attatched to bond to boxes for raceways but still use emery cloth to clean around the KO just something I was taught.

 

[infinity]

All EMT connectors are listed for bonding the raceway, there are conditions where something more than the standard lock-nut is required. Lock-nuts, even on painted surfaces, are designed to cut into the paint so removal isn't necessary.

 

[FREEBALL]

infinity, thanx for reinforcing that but I have come across locknuts that barely scratch the surface, especially Hoffman boxes, that's why I added the caveot of cleaning the surface. And another issue is making sure you have a straight cut on your conduit before placing it into your raintight fitting. And lets not even start on those that use pipe cutters on EMT.

 

[infinity]

infinity, thanx for reinforcing that but I have come across locknuts that barely scratch the surface, especially Hoffman boxes, that's why I added the caveot of cleaning the surface. And another issue is making sure you have a straight cut on your conduit before placing it into your raintight fitting. And lets not even start on those that use pipe cutters on EMT.

The locknut should be designed to cut through the paint as part of it's listing but I agree some seem to do a poor job. On painted surfaces I always tighten them with a hammer.

 

[iwire]

The locknut should be designed to cut through the paint as part of it's listing but I agree some seem to do a poor job. On painted surfaces I always tighten them with a hammer.

Exactly, I have yet to see one yet that will nut cut the paint if tightened enough.

 

[Ponchik]

The flat cast aluminum lock nuts do not do a good job compared to the steel lock nuts. I usually scrap the paint where the lock nut will end up then install the lock nut.

 

[Oishrock]

The question isn't really about the lock-nut so much as the phrasing of a "shoulders that seat firmly against the box" on the outside of the enclosure. The washer/gasket that goes against the box/enclosure on the threaded part of a raintight connector.

 

[mjc763]

The question isn't really about the lock-nut so much as the phrasing of a "shoulders that seat firmly against the box" on the outside of the enclosure. The washer/gasket that goes against the box/enclosure on the threaded part of a raintight connector. View attachment 11095

That's what I was just thinking about!

 

[infinity]

Same thing would apply on a metallic LFMC connector. The design of the connector should take into account the fact that there is gasket material on the outside and that the connector will still ground the raceway.

 

[kwired]

And you have to tighten by turning the locknut which does increase the chances of it cutting into the paint, if you turn the body of the fitting to attempt to tighten it will push out the gasket and it will not seal properly