Who knows what the purpose is for, it's code, that's all that matters. I always would cut the bushings with my Kleins and put a little gorilla glue on the seem afterwards.

And I would make sure the seem was on the back side so the inspector wouldn't see it. :laughing:

 

I've gotten very good at spotting a cut bushing :clap:

 

I've seen what happens when you omit bushings, even where not required by code. The sharp metal fittings shred the insulation like crazy.

I see putting the plastic bushing in after the fact, as completely pointless. Unless it is a local pull, where the wire is a hell of a lot less likely to be damaged.

Clever trick with the Gorilla glue. XD

 

I've put plastic bushings on after the pull when I knew the rope or string was going to queer up the bushing real bad. If you forget it completely til after terminating just cut the thing and spin it on, it'll go

 

Ohhh, that's right. I completely forgot about the rope or string.

Do ropes and strings also do that to the factory plastic end of Myers hubs and insulated EMT connectors?

 

I've been pulling 600's in and you need to take any bushing off in order for the pipe sheave to fit into conduit. Same applies when using Maxis machine . Re- install after pull

 

Always wondered if we still need bushings on metal connectors that come with the plastic inside?

 

The purpose of the plastic bushing is not intended to protect the conductors during a pull (any plastic bushing will likely burn through with the friction caused by the conductor insulation rubbing against it), but to protect the conductor insulation from rubbing on an exposed conduit edge after a pull.

All conductors will move slightly as more and less current flow through them. The mechanical movement is due to the expansion/contraction of the conductor due to heat. The larger conductors are more likely to have significant movement (hence 4 AWG and larger) due to the higher loads they carry. Over time, this movement will significantly damage the insulation thickness against a metal edge, and result in a possible ground-fault arc situation.

The other reason plastic bushings are used is to provide a larger contact area against the conductor insulation and reduce any insulation cold-flow that would occur if the conductor was really bearing down on the edge of the conduit opening (i.e. too tight of a conductor exit radius or conductors pulled too tight inside enclosure). Over time, the insulation will flow away from the high point load of the sharp conduit edge, and reduce the conductor insulation thickness. As a result, there may be a possible ground-fault arc situation.

The split plastic bushing design is the industry's first code-compliant and UL Listed solution to eliminate the need to replace a damaged bushing and cut/glue/hide a new bushing.

 

How about when you put a connector in a double thick panel and the thread is just short enough for the bushing to not screw on.

 

That happens very often with non-metallic enclosures. The walls are extra thick.

I'd like to see a combination bushing/locknut fitting, which allows for both mechanical continuity and wire abrasion protection. And where needed, electrical continuity to a jumper and waterproofing.

I know about bonding Myers hubs, but I'm talking about a situation where you already have a male conduit end that is just too short for your needs. No innuendo intended.

 

 

I think a bushing would be helpful either before the pull or after.