Plastic bushing

[stafelectric@yahoo.com]

Do you think that it would be right to say plastic bushing are only needed
for conduits with wire 6awg and bigger,on the end you pull the wire in to.

 

[fishin' electrician]

Off the top of my head, see 300.4(F) and the individual conduit articles.

 

[raider1]

Do you think that it would be right to say plastic bushing are only needed
for conduits with wire 6awg and bigger,on the end you pull the wire in to.

Where insulated fitting are required by 300.4(F) (2005) or 300.4(G) (2008) You are required to install them on each end of the raceway.

Chris

 

[infinity]

RMC would need a bushing for any size conductor. EMT #4 and larger.

 

[jaylectricity]

I guess I've been wasting money on bushings. I put them on any fitting 3/4" and above. That's the way my old boss taught me and it stuck.

 

[don_resqcapt19]

RMC would need a bushing for any size conductor. EMT #4 and larger.

But for the smaller conductors the bushing for RMC is not required to be an insulated bushing.

 

[infinity]

But for the smaller conductors the bushing for RMC is not required to be an insulated bushing.

Yes I agree. We've used metallic bushings with a one locknut on the outside for years.

 

[jeremysterling]

Do you think that it would be right to say plastic bushing are only needed
for conduits with wire 6awg and bigger,on the end you pull the wire in to.

Since I typically destroy them during the wire pulling process, I usually install them after I pull, but before I terminate.

 

[electricmanscott]

I guess I've been wasting money on bushings. I put them on any fitting 3/4" and above. That's the way my old boss taught me and it stuck.

Just think of how wealthy you could have been!

 

[tkb]

Yes I agree. We've used metallic bushings with a one locknut on the outside for years.

I haven't looked it up, but I think that only good until you go over 250 volts to ground, then you need double locknuts.

 

[wawireguy]

Since I typically destroy them during the wire pulling process, I usually install them after I pull, but before I terminate.

Are you installing them for show? I'd rather have them in before I pull to help protect the wire as it's being pulled.

 

[infinity]

I haven't looked it up, but I think that only good until you go over 250 volts to ground, then you need double locknuts.

Would an EMT connector have two locknuts?

 

[donselectric]

i believe they are temp rated blue i think was 90 deg and yellow was 105

 

[jaylectricity]

Just think of how wealthy you could have been!

I know! Literally hundreds of quarters...down the drain! Hahahaha...

 

[stafelectric@yahoo.com]

Maybe i did not get the question across right.I was saying,do you think one bushing would be sufficient on the end your feeding the wire in too.I mean what is the purpose when the wire is not moving against the connector?

 

[iwire]

Maybe i did not get the question across right.I was saying,do you think one bushing would be sufficient on the end your feeding the wire in too.I mean what is the purpose when the wire is not moving against the connector?

No, as has been said if a bushing is required at all, it is required at all ends. The NEC does not care which end you feeding the wires into.

The good it does has to do with not letting the conduit or fitting from cutting into a conductor that is pressing against it. After a long period of time it could press through the insulation after many heating and cooling cycles.

 

[dduffee260]

We put plastic bushings mostly on 1" to maybe 1 1/4". On most anything 1 1/2" and up, it depends on what we are doing. We use metal bushings, grounding bushings where they are required. On anything 3" and 4" we use metal bushings period. Do you know how expensive it can get to lose a 2000 amp service because you wanted to save $20 on the pull box and $4 on a bushing?

I know of a contractor who blew up 2 services of 2000 amps because of this very reason. These were not short runs either, they were prabably 140ft runs each time, on the same service even. I bet that larger pull box and metal bushings were not near as expensive as the service repull on this. Too many times I have seen 500 kcmil pulled at an angle where it bends the plastic bushing to the point of breaking then the wire rubs and you get a fault. Come on someone, think about what you are doing before you try to save money.

 

[don_resqcapt19]

... On anything 3" and 4" we use metal bushings period. Do you know how expensive it can get to lose a 2000 amp service because you wanted to save $20 on the pull box and $4 on a bushing? ...

I hope the metal bushings have an insulated insert as that is required.

 

[dana1028]

Since I typically destroy them during the wire pulling process, I usually install them after I pull, but before I terminate.

So now you destroy the wire and save the bushing.!!

 

[macmikeman]

Some specs I come across require them on conduits for communications wiring also no matter what size run.