• We will be performing upgrades on the forums and server over the weekend. The forums may be unavailable multiple times for up to an hour each. Thank you for your patience and understanding as we work to make the forums even better.

Improper Use of Fittings

Merry Christmas
Status
Not open for further replies.
iwire

iwire

Moderator
Staff member
Location
Massachusetts
joe tedesco said:
Go to www.nema.org and see the ppt file identified below on how fittings are supposed to be installed.

The use of fittings used improperly is the issue!!
Click to expand...

NEMA does not make the rules, show me a NTL or NEC reference.


Scott Cline, Chairman of NFPA 70 (NEC) CMP 6 seems to feel it is not a violation.

Here is some info sent to me from another forum.

MDShunk said:
That is the latest puzzle, indeed. Joe Tedesco brought this to light a couple of months ago. There are, indeed, fittings designed expressly for this purpose. People often call these "combination couplings". It would be a fitting designed, in this case, to change from EMT to FMC, without using a RMC coupling.

This information was related to me this morning from Scott Cline, Chairman of NFPA 70 (NEC) CMP 6, about a very similar installation:

Q: The installation shown in the image is not the intended application or
listing recognized by Underwriters Laboratories (UL) and VIOLATES 110.3(B).

A: My U.L. Code representative disagrees with you. He sees no violation of
listing. Given that the connector/locknuts are properly tightened, the application meets the listing.

Q: As I interpret this picture there is a malleable iron squeeze type connector
securing the flexible metal conduit. On the other end is a steel set screw connector assembled to EMT. Both connectors are joined to a coupling with the connectors locknuts made up tight (?) to the coupling.

A: We agree as to what the picture shows. (Any application is reliant on proper workmanship regarding tightening of the parts. Unless egregious, a picture cannot show a failure to properly torque.)

Q: First, a connector cannot be used as a coupling unless so listed.

A: The connector is not used as a coupling; it is used as a method of connecting its raceway to the thread of the coupling.

Q: Second, connectors have not been UL tested for resistance or ability to carry potential ground fault current when assembled to a coupling.

A: Connectors ARE tested for application to threaded connections. The mating threads of the coupling and the threads of a conduit body, etc., are the same.

Q: Third, the threads of the connectors may not match those of the coupling
raising the risk of connector pulling out of the coupling.

A: The male and female threads of electrical fittings are all made to the same
NEMA standards. They are specifically made this way so that the installation of various parts and various brands will mate properly.

Q: Fourth, there is no assurance that locknut(s) will not loosen.

A: The assurance of a locknut or of any fitting not loosening over time is proper installation workmanship. This is irrelevant to the various allowable combinations of fittings.

Q: A better choice for this installation would have been couplings designed and listed for the application. Fitting manufacturers such as O/Z-Gedney offer such a coupling for trade sizes 1/2" EMT - 3/8" FMC up to 2" EMT - 2" FMC; Bridgeport Fittings has sizes 1/2" EMT - 3/8" FMC up to 1"EMT - 1" FMC.

A: Single-purpose fittings such as those you mention would certainly be
appropriate. They might even save on installed cost, but they are not the only correct solution.

Mr. Cline offers the following, in summary:

The pictured installation does not appear to show a violation of 300.10's requirements for metallic continuity. It does not appear to show a violation of 300.15 in general, or 300.15 (F) in particular. It does not appear to show a violation of 358.42. Indeed, the screws and the connector's main thread/locknut appear to be fully seated.

Now that I offer that opinion of one man, I offer you this commentary of my own. Mr. Cline's opinion appears to run counter to NECA 1-2000, NEMA RV-3, NEMA FB2-10, and NEMA 2-20.

We'll just have to wait and see how this plays out in the end. It's causing quite a stir in the mean time.
Click to expand...

My conclusion is that it is neither a NEC or UL violation.

Because of that all NEMA can do is recommend that we do not do it.
 
joe tedesco

joe tedesco

Senior Member
Location
Boston, Massachusetts
Fittings

Fittings

Pierre:

I already posted the power point link in message #15 above,

http://forums.nema.org/wb/upload/2003-1-Field-Rep-Training-FittingsInstall.ppt

and if you look there the same one identified in the installation guidelines in the link here will take you to the same PPT file, it is a power point file and there are no other items.

By the way the Article 300 rule was put into the NEC about specific fittings long ago, and it was a proposal by a Portland, Oregon Electrical Inspector who was having trouble making it clear to some that use of a LFMC fitting was not designed to be used for FMC, the types are those inside, and with the angle screw that looks like an EMT fitting.

Please download the file above and use it to show the industry where the fittings that are shown, especially the combination fittings are the correct types.
 
Last edited:
tom baker

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Its what I would call the truck answer.
I never run FMC. If I run LTMC, T&B makes a neat female connector for RMC to LTMC, But you have to order them as none carries in stock.
 
joe tedesco

joe tedesco

Senior Member
Location
Boston, Massachusetts
In Conclusion!

In Conclusion!

joe tedesco said:
Let's just say that we are in the minority here, and that some feel that they can mix and match listed fittings anyway they want in spite of 110.2!

Comments about NEMA, not being an authoritative source are hilarious, and the members of the NEMA companies will agree with us, and others here who are aware of the poor workmanship.

The issue is one clearly defined - use the proper fittings for the purpose intended.

Who from the Inspection Community agrees with the opposition here?

Question:

Can anyone show us the text and images and training guides in the materials from the union and non-union shops that teach the methods shown in the picture?
Click to expand...

In conclusion!

"From NECA 1, 2006, Article 10, Section K:

k) Raceway(s) to equipment subject to vibration shall be terminated in a box and final connections made with flexible conduit. The box shall be located as close as practical to the equipment terminals.

From NECA 1, 2006, Article 8, Section N:

n) When terminating in threaded hubs, the raceway shall be screwed tightly into the hub. The shoulder of a fitting shall rest securely against the hub."
 
joe tedesco

joe tedesco

Senior Member
Location
Boston, Massachusetts
See 90.5(C)

See 90.5(C)

Ryan:

90.5(C) covers this subject veryclearly, and we understand that the FPN's (all 1068 of them) are not enforceable, however, ignoring them can become a problem since many include references to rules, and other documents or publications.

I am sure we agree that you are correct in your reply, and will not argue that.

The authors of the NECA documents have some responsibility too, and I hope that they will take a more careful look at their recommendations, maybe by either allowing or disallowing the issues here.

By the way the diagram in their publication shows the typical transition we all are are aware of.

I thought that there was some proposal to remove references to the NECA pubs?
 
kingpb

kingpb

Senior Member
Location
SE USA as far as you can go
Occupation
Engineer, Registered
I know you guys have been beating this around a while, what I am wondering is how is it all supported? Doesn't the felxible conduit need to be supported within a certain distance of the coupling to keep it from wanting to pull the set screw connnector from the EMT. Is the EMT set screw connector designed for supporting the coupling/flex assembly?
 
jaylectricity

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
kingpb said:
I know you guys have been beating this around a while, what I am wondering is how is it all supported? Doesn't the felxible conduit need to be supported within a certain distance of the coupling to keep it from wanting to pull the set screw connnector from the EMT. Is the EMT set screw connector designed for supporting the coupling/flex assembly?
Click to expand...

If support was the issue I'm sure Joe would have brought that up. On the other hand he DID bring up vibration in one of his last posts, but if that was the real argument it should have been brought up last year when the thread was started.

It just seems like a case where one person picked out one application in one situation and tried to make that proof in itself that the application should NEVER be used. What was not included was:

1. Specific text from the website he was plugging.
2. Specific text from the company he was plugging.
3. Specific tangible negative RESULTS of the application.

Keyword: specific

I take the original poster with a grain of salt but I did learn a few things by reading the entire thread.
 
ryan_618

ryan_618

Senior Member
Location
Salt Lake City, Utah
mdshunk said:
If you totally ignore them, particularly NECA 1, what on earth do you use for 110.12 guidance?
Click to expand...
I don't use anything. If the installer follows the prescriptive rules of the code, such as for securing and supporting, I pass the installation. 110.12 is far too subjective, and does not create any safety hazards.
 
Tori

Tori

Senior Member
Location
Maryland
A jw was explaining to me the other day about how he used 4" emt compression coupling to join 4" pvc together
He was proud of his quick thinking and how well it fit
I told him it violated code and was improper use of fittings but listening to you all talking about grounding paths that would not be an issue here -

so why the big arguement ? Pvc plumbing pipe fits our fittings but is also code violation

Joe - the arguement is not about grounding path but is the fitting listed for the application
 
Status
Not open for further replies.
Top