# Installing bushings after the pull



## Carultch (May 14, 2013)

I was browsing conduit fittings, and I found this catalog from Bridgeport:
http://www.bptfittings.com/Public/D...alog/MightyRite Split Bushings Sell Sheet.pdf

I understand the need for split bonding bushings. Helpful for the "whoops, I forgot" situation when you forgot you needed a more substantial ground on the conduit, after the pull. Remove the plastic bushing, snip it, and pop on the split bonding bushing.

What about split plastic bushings? Any reason why you'd install this after the pull? Other than the case of "whoops, I forgot I need this for #4 and larger", does it do anything for you if you add this after the pull? I thought the whole purpose of the bushing is to prevent wire abrasion during the pull.


----------



## MHElectric (Oct 14, 2011)

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:


----------



## Carultch (May 14, 2013)

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


----------



## ponyboy (Nov 18, 2012)

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


----------



## 360max (Jun 10, 2011)

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


----------



## Carultch (May 14, 2013)

ponyboy said:


> 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?


----------



## Southeast Power (Jan 18, 2009)

ponyboy said:


> 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


Queer up the bushing?

I'm going to try to use that out of context at least 10x this week. :laughing:


----------



## ponyboy (Nov 18, 2012)

Carultch said:


> 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 honestly don't know but I know strings and ropes make mincemeat out of terminal adapters and plastic bushings.


----------



## eddy current (Feb 28, 2009)

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


----------



## manchestersparky (Mar 25, 2007)

MHElectric said:


> 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:


----------



## LJSMITH1 (May 4, 2009)

Carultch said:


> I was browsing conduit fittings, and I found this catalog from Bridgeport:
> http://www.bptfittings.com/Public/D...alog/MightyRite Split Bushings Sell Sheet.pdf
> 
> I understand the need for split bonding bushings. Helpful for the "whoops, I forgot" situation when you forgot you needed a more substantial ground on the conduit, after the pull. Remove the plastic bushing, snip it, and pop on the split bonding bushing.
> ...


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.


----------



## MHElectric (Oct 14, 2011)

manchestersparky said:


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


:laughing:

So....do you make them tear it out, and put a new one in? :detective:


----------



## Aegis (Mar 18, 2011)

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.


----------



## Carultch (May 14, 2013)

Aegis said:


> 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.


----------



## RAD COM (Mar 3, 2019)




----------



## RAD COM (Mar 3, 2019)

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


----------

