RNC and metallic locknuts

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fracas666

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Article 352.100
Rigid Nonmetallic Conduit (RNC) construction specifications states that RNC and fittings shall be composed of suitable nonmetallic material that is resistant to moisture and chemical atmospheres.

Article 100 Definitions
Fitting. An accessory such as a locknut, bushing, or other part of a wiring system that is intended primarily to perform a mechnical rather than an electrical function.

Does this mean that metallic locknuts cannot be used with RNC male adaptors? If so, are PVC locknuts produced over one inch? If not then I guess that all of these years I should have been using PVC box connectors for connecting to electrical enclosures. Also would a strap be considered a fitting, as it is part of a wiring system that is intended primarily to perform a mechanical function? This would answer the question of using metallic straps on PVC.

Ron
 
Why has there been no replies to this question? Is it such a stupid question that it doesn't warrant a reply? Has everyone known what is stated to be true for years and I'm the last to come this realization?

From what I read in the code I think that I am correct in that you cannot use metallic locknuts with RNC male connectors. Was this what the NFPA intended to do? Are conduit supports considered fittings?

Ron
 
fracas666 said:
Article 352.100
Rigid Nonmetallic Conduit (RNC) construction specifications states that RNC and fittings shall be composed of suitable nonmetallic material that is resistant to moisture and chemical atmospheres.


Does this mean that metallic locknuts cannot be used with RNC male adaptors? .

Ron
Click to expand...
Of course not...
352.48 Joints.
All joints between lengths of conduit, and between conduit and couplings, fittings, and boxes, shall be made by an approved method.
 
fracas666 said:
Are conduit supports considered fittings?
Click to expand...

Ron I agree that per the definition of fitting supports could indeed be called fittings.

However if we apply it that way we run into more problems.

Many raceway supports are not listed at all.

All the raceway articles require the use of listed fittings.

I have always used metal locknut's on RNC but that may not be the right thing to do.

Perhaps I should change to box adapters they do not use lock nuts.
 
celtic said:
Of course not...
352.48 Joints.
All joints between lengths of conduit, and between conduit and couplings, fittings, and boxes, shall be made by an approved method.
Click to expand...

The question is, is a metallic locknut an approved method?
Ron
 
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Jim W in Tampa said:
If they are not for lock nuts then what should we use on MA
Click to expand...

From what I read we can only use PVC locknuts on the male adapters. I have only found them in 1/2, 3/4, and 1 inch sizes. Maybe the conduit and fitting manufacturers have not realized that they should be making them. Maybe the code panel did not intend to create this dilemma.
Ron
 
fracas666,

What is the deal with 666??? If it is an inane question then I am sorry. God Bless you.

Iwire,

"I have always used metal locknut's on RNC but that may not be the right thing to do.

Perhaps I should change to box adapters they do not use lock nuts."

Pardon my ignorance but what is a box adapter?
 
If anyone here can provide even a remotely reasonable situation or condition in which the use of metal lock nuts on PVC fittings could present a hazard, I may spend a moment considering the issue a little more. Unitl then, I think the arguement is silly.

Though the definition of fitting includes locknuts, I don't believe the use of fitting in 352.100 is intended to include that specific part of the fitting component.
 
JJWalecka said:
Pardon my ignorance but what is a box adapter?
Click to expand...


It is this

474559364d435a55666f57317938346741-100x100.jpg


You slip it through the KO of the enclosure from the inside than glue a coupling or bell end over it.

No lock nut or bushing needed, the inside looks like a chase nipple.
 
>Does this mean that metallic locknuts cannot be used with RNC male >adaptors?

If this were true then a lot of inspectors are 'doing their own thing' in the field because none are ever cited as a violation.

Taking this reasoning further, you could not screw a male adapter into a rigid (galvanized) coupling to convert from pvc (below grade) to RGC or EMT above grade.
 
Bob,
Ron I agree that per the definition of fitting supports could indeed be called fittings.
Click to expand...
I thought so too, but the CMP 8 doesn't agree.
8-5 Log #2239 NEC-P08 Final Action: Reject
(342.6 Exception (New) )
________________________________________________________________
Submitter: Donald A. Ganiere, Ottawa, IL
Recommendation: Revise as follows:
342.6 Listing Requirements. IMC, factory elbows, and couplings, and associated fittings shall be listed.
Exception: Raceway support fittings and accessories shall not be required to be listed.
Substantiation: The Article 100 definition of “fitting” seems to include raceway supports. Many of the commonly used raceway support straps, clamps, and other items are not listed.
Panel Meeting Action: Reject
Panel Statement: Conduit support accessories are not considered “Fittings”. Sections 300.6 and 300.6(A) require support hardware to be constructed of materials suitable for the environment for which they are to be installed.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12
Click to expand...

Don
 
Fracas666,

As in the PM I sent you, I once again apologize for my misconception.




Iwire,


Thank you. I have never seen a box adapter.

Justin J. Walecka
 
fracas666 said:
Article 352.100
Rigid Nonmetallic Conduit (RNC) construction specifications states that RNC and fittings shall be composed of suitable nonmetallic material that is resistant to moisture and chemical atmospheres.
Ron
Click to expand...


We did a YMCA with 2 big pools, so everything had to be PVC because of the chemicals. After reading that I would say the locknuts we used probably should have been nm. I would imagine that it isn't gonna hurt anything though but I could see where it could pose a threat if in the right place.
 
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