PVC Junction Box

[petersonra]

Support it with nails instead of screws

 

[tom baker]

Only way I've ever seen it done. It seems the only other way is with a box adapter and glue. Do they even make a plastic locknut? All I find is plastic bushings.

-Hal

Yes plastic locknuts are avaiable. They don't bite into the box like metal. I would use in wet locations in vaults, typically on cords to instruments, connections in box are waterproof.

 

[jap]

Support it with nails instead of screws

Just make sure you're mounting the PVC box to a non conductive wooden structure, or, if your mounting it to a conductive metal structure, just make sure the structure is bonded and grounded per code.

JAP>

 

[electrofelon]

So what section would require bonding of the locknut? One could, of course, use a grounding locknut if it is required to be bonded.

Cheers, Wayne

I think this is a good question no one has answered. I would answer but I haven't been by my codebook lately. 250.92 may apply, but there are other parts of 250 that broadly require stuff to be bonded/connected to an EGC. IIRC they don't all use the phrase "likely to become energized" so I don't think one can make the case that it is not likely to be energized thus it doesn't require bonding

 

[Dennis Alwon]

There is nothing that I can find that states specifically about a locknut however we all know that a non-metallic box has a recess for the head of a screw to be kept from touching a wire so why would that be different for a locknut.

314.43 Nonmetallic Boxes. Provisions for supports or other
mounting means for nonmetallic boxes shall be outside of the
box, or the box shall be constructed so as to prevent contact
between the conductors in the box and the supporting screws.

Then there is article 250 which states all metal parts likely to be energized shall be connected together.....

So in the one example a screw is considered likely to be energized but is a locknut considered likely to be energized. I think it is an authority having jurisdiction call at best.

 

[augie47]

I may be missing a relevant Section but looking at bonding and grounding requirements I don't see anything that would require them to be grounded (bonded)

250.96 Bonding Other Enclosures. (A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non– current-carrying parts that are to serve as equipment ground ing conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them.
and grounding:
250.110 Equipment Fastened in Place (Fixed) or Connected by Permanent Wiring Methods. Exposed, normally non–currentcarrying metal parts of fixed equipment supplied by or enclos ing conductors or components that are likely to become energized shall be connected to an equipment grounding conductor under any of the following conditions:

 

[electrofelon]

I may be missing a relevant Section but looking at bonding and grounding requirements I don't see anything that would require them to be grounded (bonded)

250.96 Bonding Other Enclosures. (A) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other metal non– current-carrying parts that are to serve as equipment ground ing conductors, with or without the use of supplementary equipment grounding conductors, shall be bonded where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them.
and grounding:
250.110 Equipment Fastened in Place (Fixed) or Connected by Permanent Wiring Methods. Exposed, normally non–currentcarrying metal parts of fixed equipment supplied by or enclos ing conductors or components that are likely to become energized shall be connected to an equipment grounding conductor under any of the following conditions:

I suppose "fittings," in 250.96 could cover it. I would say a lock nut itself is not a fitting, but it is a component of a fitting.

 

[synchro]

I may be missing a relevant Section but looking at bonding and grounding requirements I don't see anything that would require them to be grounded (bonded)
...
250.110 Equipment Fastened in Place (Fixed) or Connected by Permanent Wiring Methods. Exposed, normally non–currentcarrying metal parts of fixed equipment supplied by or enclosing conductors or components that are likely to become energized shall be connected to an equipment grounding conductor under any of the following conditions:

Also, even if the lock nut does become energized it is not "exposed" if it's completely inside of the non-metallic box. In contrast, a mounting screw passing through a hole in the box would have its threaded portion exposed on the outside of the box.

 

[GoldDigger]

Also, even if the lock nut does become energized it is not "exposed" if it's completely inside of the non-metallic box.

When the box is open the part is exposed. But you should not be working hot.
The head of a screw or nail is not exposed when the box is closed either, but the body of the screw is definitely outside the box, although usually at least partially embedded in wood.

 

[brantmacga]

10-4. Don't know if this applies, or is legal, I have used a PVC reducer bushing into a PVC coupling with cement to secure pipe coming into a PVC box. 1x3/4 bushing into 1"coupling with 1x3/4 bushing to conduit. pretty watertight.
View attachment 2557299

That’s essentially what a PVC TA (I’ve also seen labeled as “box adapter”) is; it’s like a chase nipple, but without threads, and glues into a PVC coupling.

Edit…. I think what I call a male adapter everyone else calls a terminal adapter…. Maybe box adapter is the more appropriate common term for what I’m referring to.

And yes, I’ve also used male adapters with lock rings inside a pvc pull box.


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[Little Bill]

That’s essentially what a PVC TA (I’ve also seen labeled as “box adapter”) is; it’s like a chase nipple, but without threads, and glues into a PVC coupling.

Edit…. I think what I call a male adapter everyone else calls a terminal adapter…. Maybe box adapter is the more appropriate common term for what I’m referring to.

And yes, I’ve also used male adapters with lock rings inside a pvc pull box.


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Yes
TA = Male Adapter
Box adapter is all I know to call the fitting that goes into the coupler. Actually, that's what is listed on my SH tickets.

 

[electrofelon]

Yes
TA = Male Adapter
Box adapter is all I know to call the fitting that goes into the coupler. Actually, that's what is listed on my SH tickets.

Yes TA = male adapter, box adapter is thing that goes into a female. I wasn't aware there was any ambiguity with this.

 

[Carultch]

Yes TA = male adapter, box adapter is thing that goes into a female. I wasn't aware there was any ambiguity with this.

A box adapter is not the same thing as a male adapter / terminal adapter.

A box adapter is the PVC equivalent of a chase nipple. It plugs in to the flared end of the PVC, or the PVC coupling on one side, and has its own flared end to connect to the enclosure. It is an irreversible connection to terminate conduit this way, so it will require cutting the raceway apart if you want to remove the boxes.

A male adapter and a terminal adapter are two interchangeable terms for the same fitting. It is a PVC fitting that puts male threads on your terminations of PVC conduit, which is usually used in combination with a plastic bushing and locknut to complete its termination to an enclosure. It can connect in to its female adapter counterpart, but this is rare, as it is more common to simply use a coupling. The female adapter is more often used for transitioning to threaded RMC or IMC conduit, or connecting a cord grip to the conduit termination.

 

[electrofelon]

A box adapter is not the same thing as a male adapter / terminal adapter.

I agree, that is what I meant in my previous post.