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During the last inspection visit, I was told that the pvc sch80 conduits I have needed to have some sort of fastening/clamp to secure the cable at the top of the sch80 pipe. Even though I had chamfered the inside edges to avoid cable damage, according to the inspector there is some sort of adapter to the 3/4 or 1" sch80 pipe that can fasten it to the tip of the pipe. Is anyone aware of such a thing or similar fastening alternative? I have searched high and low, but my google-fu must be weak.

I am also uncertain that a clamp is even required per the NEC 2017, so if anyone has commentary about that, it would also be welcome.

These are my drier/washer pvc sch80 runs, straight down 6ft until they terminate in applicable boxes:

enter image description here

This is what I believe the inspector wants to see at the top of each one. I can take the cable out and the pipe off the wall and extend/reduce it's length, no problem. Is there an adapter or some other version of such a clamp that allows to attach it to the top of the pipe?

enter image description here

sil80
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2 Answers2

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The fitting you want is a bell end

Your inspector is correct that a fitting is needed there; however, there is no equivalent fitting to an EMT-to-NM or RMC-to-NM adapter clamp for PVC conduit. Instead, you need to use a bell end fitting on the conduit, then secure the cable separately.

ThreePhaseEel
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  • Thank you ThreePhaseEel - I'm getting different results for bellend fittings - 1) https://www.homedepot.com/p/3-4-in-90-Degree-Bell-End-Elbow-R5233824/202043345 2) https://www.platt.com/platt-electric-supply/PVC-Bell-Ends-Ends/Multiple/1PBE/product.aspx?zpid=69081 For that first one, I am not sure how to used except that it would extend the pvc pipe up and turn along the joist and I could staple the cable as it comes out of the bell end. The second one I really don't get outside of being a better version of a bushing, and still would staple the cable within what 8" of it? – sil80 Jul 28 '21 at 14:33
  • I couldn't edit my comment to reflect what I think is what you meant - Thank you ThreePhaseEel - I'm getting different results for bell end fittings - Is this what you're referring to? https://www.platt.com/platt-electric-supply/PVC-Bell-Ends-Ends/Multiple/1PBE/product.aspx?zpid=69081 It looks like a a better version of a bushing, and I still would staple the cable within 8" of the bell end? I'm totally ok with that just want to make sure I understand what is what. – sil80 Jul 28 '21 at 14:43
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    @sil80 yeah, that's the correct style of fitting. You'll still want to staple the cable, of course, though – ThreePhaseEel Jul 28 '21 at 22:31
  • Just out of curiosity, is there code for the bell end vs. the bushing pictured below, and what is your take on the difference in function each performs, or is it a case of "one is rated to do the job and the other isn't"? – sil80 Jul 29 '21 at 12:04
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    @sil80 -- a bell end is used when a PVC conduit dumps out into empty space (wall cavity, switchrack or padmount wiring compartment). A bushing is used when fat wire (4AWG or fatter) exits a conduit into a box (regardless of the type of conduit involved, or whether a fitting is used to couple the conduit to the box) – ThreePhaseEel Jul 30 '21 at 01:04
  • Many thanks as always, ThreePhaseEel! – sil80 Jul 30 '21 at 16:37
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You don't usually see a clamp there, but the inspector may want a listed bushing to be sure that no damage occurs. A similar scenario is where conduit connects to a service panel. You'd cement on a male thread fitting first.

You'd then want to staple the cable within 12" of that bushing, such as to the adjacent joist. I can't imagine that not being adequate.

Since it would be a hassle to get the bushing on there now, I'd start with the staple.

enter image description here

isherwood
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  • That was my thought as well - bushings I know about and have actually put on since the picture was taken. Clamps on top of the conduit I have only seen on EMT conduit, but that does give me pause - if the EMT conduit requires the clamp, it's odd that pvc sch80 does not. – sil80 Jul 27 '21 at 13:55
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    This is a pretty common scenario with furnace wiring, for example, where conduit extends up into the ceiling framing and then terminates. I've never seen a clamp required there--just proper stapling. I'm not an electrician, though. – isherwood Jul 27 '21 at 13:58
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    @isherwood I do think the inspector is thinking of something like the bottom-most image in this answer (https://diy.stackexchange.com/a/12063/36011) that you would find on the end of EMT when running NM through it. I haven't done enough wiring with PVC to know if the same thing exists or is even required for PVC. – statueuphemism Jul 27 '21 at 14:01
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    With EMT you don't usually staple anything. Thus, clamps. We have some knowledgeable sparkies around that will tell us if I'm wrong. – isherwood Jul 27 '21 at 14:04
  • I hope so! I am no electrician, and I know there are certain times when clamping is required, but to clamp it to the conduit instead of the nearby joist... well, again if there are some fittings or adapters that make that possible, why not, I just haven't found any. Hope someone can clear it up! – sil80 Jul 27 '21 at 23:20