NEC 353.12.1, 353.48, 355.48 Questions about using an adhesive

[freddyt7]

Hi - this part of the code states that you HDPE (PE roll pipe) can not be allowed to be above ground. In this case you need to transition from the HDPE pipe and then come up out of the ground with PVC or GRS.

Secondly, the code states that you can use an accepted method of joining or a mechanical device. In the case of wanting to use a bell ended PVC sweep mechanical seals don't work.

PVC pipe cement does not adhere to HDPE and is NOT accepted by the HDPE conduit manufacturers. They do allow when you go from pipe to pipe mechanical couplings, push on couplings or reverse threaded couplings and an adhesive called BonDuit. Which BonDuit adhesive, threaded and push on couplings are not mechanical. However. they are approved by the manufacturer.

If you were the AHJ and you saw the contractor had to meet the NEC code where they had to come out of the ground and had to transition between dissimilar conduit materials and they used an approved adhesive (letters from the conduit manufacturers) would you accept that as an approved method? The same goes for pipe to pipe underground using a push on non-mechanical coupling that was approved by the conduit manufacturer?

Finally, PVC pipe cement is an approved method for PVC pipe joining but does not have any UL mark. So, some of the above solutions also do not have UL marks.

Thank you for your time and consideration.

 

[texie]

I see no reason why it should not be approved by the AHJ. I don't see an alternative if that is what the manufacturer offers.

 

[PaulMmn]

Is it PVC or another variety of plastic that requires using a primer-- purple in color-- before the glue. And the plumbing (?) inspectors look for the primer color before approving the piping.

I don't know if this is also the case with electrical piping or not.

 

[hbiss]

We don't use primer with PVC.

Wouldn't it be easier just to use a male adapter on both conduits (HDPE on HDPE, PVC on PVC) then a threaded coupling? Nobody is going to argue with that.

-Hal

 

[Carultch]

We don't use primer with PVC.

Wouldn't it be easier just to use a male adapter on both conduits (HDPE on HDPE, PVC on PVC) then a threaded coupling? Nobody is going to argue with that.

-Hal

Unless you are thinking of something other than an RMC coupling, you are introducing a metal fitting in the middle of a plastic raceway system, and have no way of grounding it. Granted, underground metal sections without bonding in the middle of a PVC run, are allowed,provided it remains 18" below grade.

Is there any reason the OP wouldn't be able to combine a PVC female adapter, with the HDPE male adapter? That's the solution that would come to my mind first, if I were trying to solve this problem. I'm not familiar with HDPE conduit, other than knowing that it exists and what HDPE stands for, so I don't know the details of what an HDPE male adapter looks like.

 

[freddyt7]

We don't use primer with PVC.

Wouldn't it be easier just to use a male adapter on both conduits (HDPE on HDPE, PVC on PVC) then a threaded coupling? Nobody is going to argue with that.

-Hal

The problem is that mechanical push on or reverse threaded couplers come apart easily and PVC pipe cement does not work on HDPE pipe. I am asking about an approved adhesive that works on HDPE to PVC. The threaded PVC adapter would be used on the HDPE pipe when required to go to GRS above ground. Utilities for example will have this on riser poles at intersections.

 

[freddyt7]

Unless you are thinking of something other than an RMC coupling, you are introducing a metal fitting in the middle of a plastic raceway system, and have no way of grounding it. Granted, underground metal sections without bonding in the middle of a PVC run, are allowed,provided it remains 18" below grade.

Is there any reason the OP wouldn't be able to combine a PVC female adapter, with the HDPE male adapter? That's the solution that would come to my mind first, if I were trying to solve this problem. I'm not familiar with HDPE conduit, other than knowing that it exists and what HDPE stands for, so I don't know the details of what an HDPE male adapter looks like.

The OD of HDPE and PVC schedule 40 is the same. So you can use standard couplings or bell ended sweeps to connect the dissimilar materials. The question I am trying to clarify is that PVC pipe cement will not work on HDPE. But their is an adhesive that does. Would an AHJ approve this method if you had letters from the HDPE conduit manufacturers to connect the pipe to meet the code. I hope I am being clear. Thank you

 

[SSDriver]

Just ask the AHJ. I would think it would be fine.

 

[Hv&Lv]

Not a solution for NEC applications, but there is an adhesive for hdpe to pvc. Not listed.

 

[freddyt7]

Unless you are thinking of something other than an RMC coupling, you are introducing a metal fitting in the middle of a plastic raceway system, and have no way of grounding it. Granted, underground metal sections without bonding in the middle of a PVC run, are allowed,provided it remains 18" below grade.

Is there any reason the OP wouldn't be able to combine a PVC female adapter, with the HDPE male adapter? That's the solution that would come to my mind first, if I were trying to solve this problem. I'm not familiar with HDPE conduit, other than knowing that it exists and what HDPE stands for, so I don't know the details of what an HDPE male adapter looks like.

HDPE does not have male or female adapters. You must use a special mechanical fitting or bridge from HDPE to PVC or GRS when going above ground. Thank you for your input.