Fittings and bushings, PVC specific...

[PetrosA]

The bushing thread reminded me of something that's been bothering me for a while. When you tap a KO into a PVC box, termads fit with a locknut and bushing, no problem. But when you have to use a metal connector for something, the threaded part is shorter and you can't fit a bushing on it. How do others solve this problem?

 

[Smart $]

The bushing thread reminded me of something that's been bothering me for a while. When you tap a KO into a PVC box, termads fit with a locknut and bushing, no problem. But when you have to use a metal connector for something, the threaded part is shorter and you can't fit a bushing on it. How do others solve this problem?

What type of bushing are you talking about?

Being you first mentioned PVC, I'm assuming you are not talking about a grounding bushing. If that is the case, I'd use an insulated-throat connector.

 

[Cow]

I sometimes have this problem when using pvc male adapters also, as not all of them have sufficient threads to poke through the box and still get a plastic bushing on. I don't know any tricks other than preplanning to make sure the problem doesn't come up.

Either use a metal box or a thinner fiberglass one, or run a different raceway type to avoid having to use short throated metal connectors. Something else that would work if you're in a pinch, it's cheesy, is to pop a chase nipple from the inside of the box out into a rigid coupling, then pop your connector into that. We've done this type of install for different reasons though, usually when we need to cut a j-box into the middle of a pipe run. It's not pretty, but it gets the job done.

 

[PetrosA]

What type of bushing are you talking about?

Being you first mentioned PVC, I'm assuming you are not talking about a grounding bushing. If that is the case, I'd use an insulated-throat connector.

I should have been more specific. I mean a fiber bushing (insulating) in a PVC j-box (4x4, 6x6 etc.). The box wall is about 3/16" or so, so if you have a metal connector or some plastic ones (flex conns) the threads are too short to fit both the locknut and a bushing. It's one of those few cases where the materials themselves work against a code compliant installation.

 

[Smart $]

I should have been more specific. I mean a fiber bushing (insulating) in a PVC j-box (4x4, 6x6 etc.). The box wall is about 3/16" or so, so if you have a metal connector or some plastic ones (flex conns) the threads are too short to fit both the locknut and a bushing. It's one of those few cases where the materials themselves work against a code compliant installation.

IMO, an insulated-throat connector will suffice. If you also have to bond, perhaps a bonding locknut will suffice.

As for plastic connectors, I didn't think an insulating bushing was required since it is constructed of an insulating material :-?

 

[Dennis Alwon]

The bushing thread reminded me of something that's been bothering me for a while. When you tap a KO into a PVC box, termads fit with a locknut and bushing, no problem. But when you have to use a metal connector for something, the threaded part is shorter and you can't fit a bushing on it. How do others solve this problem?

Not sure why you are using metal from a pvc box but I guess you could take the metal connector and add a rigid coupling to it,and then put a short nipple into the other end of the coupling.

 

[augie47]

Not sure why you are using metal from a pvc box but I guess you could take the metal connector and add a rigid coupling to it,and then put a short nipple into the other end of the coupling.

That's the method I have used in the past. On those rare occasions when I had metallic conduit involve with PVC enclosures, I found that I often needed to bond the conduit and the nipple/coupling combination gave me the opportunity to add a bonding bushing.

 

[tkb]

If you entered a PVC box with EMT or RGS, do you need a locknut on the inside of the box?
If you just used a bonding bushing on the inside and it made a tight connection, would that be code compliant?

You need a bonding bushing anyway, and this way the bushing would be installed and the conduit is tight.
If you used a locknut on the inside, you can't get the bushing on.

 

[Smart $]

If you entered a PVC box with EMT or RGS, do you need a locknut on the inside of the box?
If you just used a bonding bushing on the inside and it made a tight connection, would that be code compliant?

You need a bonding bushing anyway, and this way the bushing would be installed and the conduit is tight.
If you used a locknut on the inside, you can't get the bushing on.

Good question. I don't believe it to be a direct code violation, but I wonder if this would be a permitted use under its listing???