Bulk of my work involves relocating circuits out of MSP into a backup LC. Strictly THHN, no NM. When doing a back-to-back equipment install, I connect boxes with metallic running thread conduit cut to length instead of having to manufacture a PVC nipple; when doing side-by-side equipment mounting I typically use a gutter box for circuits. To plumb into MSP I use a malleable iron bushed elbow in wall to connect to surface mount gutter box. Elbow has male threads one end, female threads on other end. My question is, why can't I find running thread conduit or elbows constructed out of PVC? Both are in a wall where not subject to physical damage. Surely PVC is cheaper. Electrical PVC has high temp rating. Using a PVC fitting would negate the need for a ground bushing between MSP and gutter box. Any ideas?
PVC conduit fittings
- Thread starter Pahpa J
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
- Location
- Illinois
- Occupation
- retired electrician
Not sure how you can use PVC running thread as 362.6 says the PVC conduit and fittings must be listed and section 4.1.7 of UL 651, "Schedule 40, 80, Type EB and A Rigid PVC Conduit and Fittings" says rigid PVC cannot be threaded.
kwired
Electron manager
- Location
- NE Nebraska
Are the listed? Otherwise as Don mentioned PVC isn't allowed by code to be threaded, so it would about need to be a listed fitting of some sort.
Won't say I never threaded PVC before, haven't done it very many times. Usually just 1/2 or 3/4" though or for non electrical related uses.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
I dunno.
Thanks but still confused. Jurisdictions I work in allow PVC threaded terminal adapters used to make nipples to connect 2 surface mounted boxes. Are these not UL listed? Would seem if these are acceptable for outdoor applications surely a PVC elbow inside a wall would be acceptable?
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
Perhaps that only refers to PVC conduit, and if the running thread is short enough it can be considered a fitting? Because certainly male adapter / terminal adapters are threaded fittings.
Cheers, Wayne
- Location
- Illinois
- Occupation
- retired electrician
There are provisions for the male adapter in UL 651, but there are no provisions for running thread in that standard. The standard covers both the conduit itself and fittings used with the conduit.
kwired
Electron manager
- Location
- NE Nebraska
A "terminal adapter" is a listed fitting. One on each end of a short piece of PVC conduit - you have something made from listed components
Field threading of PVC conduit is not allowed by code.
I asked earlier if the "running thread" PVC nipples that were posted are listed. If they are not then they can't be used as electrical conduit or conduit fittings (and pass code inspections). I've never seen such a product that is listed for this purpose, but that doesn't mean there isn't any either. Otherwise PVC conduits must terminate in a listed fitting or a box with integral hubs designed to accept this conduit - such hubs are plain socket that you use PVC cement to secure the conduit into the hub.
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
Arlington used to make pvc chase nipples
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