MC-HL and conduit fittings

[AKElectrician]

First I have done just about every combo of MC-HL to whatever type of box or fitting "cause that's how you do it". Second I personally feel MC-HL is the highest abused product for code violations I have ever worked with, and no matter what you do unless you hide it in conduit this stuff looks sloppy 30 mins after your done making it look good and someone/wind/gravity bumps it. Third I feel that "roping" refineries and gas fields is killing off lots of conduit workmanship/knowledge. I personally have met multiple journeyman who have only made nipples and installed them, that's the extent of there conduit running, but man can they run some cable.

To the point, I can not find anywhere saying anything that conduit hubs, unions, condulet's, or other fittings are acceptable with anything other than heavy wall conduit or EMT if listed. The main combos typically done in the field are Meyers Hubs with TMC/TMC-X, UNY/UNL with TMC/TMC-X, or GUA/ L-fittings to TMC/TMCX, TMC/TMCX to couplings/RE's, also supported with straps that say on them RMC/IMC/EMT. All the classified conduit fittings are listed to be used with heavy wall conduit only as far as I can find, unless I missed something. I have been wrong thousands of times not afraid of being wrong again. I understand the whole AHJ thing, but this has become standard where I live, and have seen it done and done it everywhere whether the AHJ knows it's done or not. I also understand that most MC-HL installations would be hideous if we followed the rules to the T. But MC-HL as written by most manufacturers is to replace conduit all together cause this product is "faster,and superior to conduit". Now this may seem like a stupid question to be asking and I should just be a good copy cat and follow suit cause it works and is cheaper and faster, but with that thought process why not cut corners everywhere and install whatever works out to be easier code compliant or not. IF i am reading into this right basically two clearly classified fittings are being installed together, that have not been "tested" together. Is it unsafe? I doubt it but IF I am right it is quite the code violation in my mind. How many guys been busted using some cheap part somewhere that worked and was safe and just as good as the other cheap part they were supposed to use, but wasn't listed and they had to go back and redo all their hard work?

 

[don_resqcapt19]

From the UL White Book for "Metal-clad Cable Connectors, Type MC (PJOX).

All male threaded fittings have only been investigated for use with locknuts.

The cable connectors have not be evaluated for use with any type of female threaded fitting.

 

[AKElectrician]

From the UL White Book for "Metal-clad Cable Connectors, Type MC (PJOX).

The cable connectors have not be evaluated for use with any type of female threaded fitting.

Does this include TMC type connectors? I have searched as hard as I know how and have found the most info in catalog type sites, selling me a product that's supposed to replace conduit but not allowed to be used with female threaded fittings is not a selling point so doubt they would mention that part.

EDIT: Your right not that I thought you were wrong, possibly the funniest thing I have ever learned in my life if that is true.

 

[Smart $]

...if that is true.

It is. :happyyes:

 

[rbalex]

From the UL White Book for "Metal-clad Cable Connectors, Type MC (PJOX).

The cable connectors have not be evaluated for use with any type of female threaded fitting.

The same statement appears in "Conduit Fittings (DWTT)" and throughout the White Book for all male threaded raceways and connectors. The ultimate effect is that no threaded connection of any kind in a hazardous location is compliant with Sections 501.30(A), 502.30(A) or 503.30(A) unless it has a supplementary bonding connection. In fact, even intrinsically safe wiring has the same problem as Section 504.60 refers back to the previous mentioned 50x.30(A) Sections and 250.100. Technically, common couplings are a problem.

None of the NRTL representatives of CMP14 (6 of them) seem concerned with it though and the locknut-bushing of double locknut prohibition has been around longer than I've been in the business.

 

[don_resqcapt19]

The same statement appears in "Conduit Fittings (DWTT)" and throughout the White Book for all male threaded raceways and connectors. The ultimate effect is that no threaded connection of any kind in a hazardous location is compliant with Sections 501.30(A), 502.30(A) or 503.30(A) unless it has a supplementary bonding connection. In fact, even intrinsically safe wiring has the same problem as Section 504.60 refers back to the previous mentioned 50x.30(A) Sections and 250.100. Technically, common couplings are a problem.

None of the NRTL representatives of CMP14 (6 of them) seem concerned with it though and the locknut-bushing of double locknut prohibition has been around longer than I've been in the business.

Bob,
I don't agree that it applies to threaded IMC and Rigid conduits. The White Book information for things like conduit bodies and conduit hubs specify that that they are for use with the male threads on Rigid and IMC.

 

[rbalex]

Don, First and foremost, Happy Thanksgiving old friend.

From the UL White Book, the scope of Conduit Fittings (DWTT):

This category covers metallic and nonmetallic conduit fittings, such as
connectors, couplings, conduit bodies, short-radius conduit bodies, expan-
sion ttings, locknuts and sealing (liquid-tight) locknuts for use in the
assembly of nonmetallic and metallic wiring systems.

The same Category Code (CC) acknowledges "Some of these fittings are also suitable for use in certain hazardous (classified) locations where unclassied locations fittings are permitted in Articles 501, 502, 503, 505 and 506 of the NEC."

Then again, TMCX fittings fall under Category Code CYMX rather than PJOX with no reference to locknuts. I no longer have access to the UL standards, but I don't see a cross reference between the basic test standards, ANSI/UL 2225 (CYMX) of and 514B (PJOX) that would place a "locknut" restriction on TMCX fittings.

My position is that fittings that are otherwise acceptable in classified locations with 5, 4-1/2, or 7, threads engaged are also suitable [Section 500.8(A)(3), if necessary] to comply with Section 50x.30(A) depending on the application. [Note Section 50x.30 makes no significant distinction between Division 1 and 2.] Absent a specific prohibition in Section 500.8(E) or a Formal Interpretation to the contrary, I will maintain that position.

I was on a different CMP in the mid-90s, but I warned CMP14 that introducing Zones to the NEC would open a can of worms when Zone equipment started affecting Divisions. I actually proposed the forerunner of MC-HL through API to avoid Zones. The real purpose of "Division 0" or Zones was to reduce weight on offshore drilling rigs and allow lower weight IEC type equipment. The threading issues of Section 500.8(E) were introduced "harmonizing" NPT with metric threads.

 

[AKElectrician]

The real purpose of "Division 0" or Zones was to reduce weight on offshore drilling rigs and allow lower weight IEC type equipment.

No weight saved if you account for all the supports needed for MCHL unless you run cable tray everywhere and that's not practical on a old platform. Strut is heavy and supports every 6 feet is pretty fun when you could do it every 10' if you ran conduit. Also supporting 12" from a MCC is a really good time:happyno:.

 

[AKElectrician]

Don, First and foremost, Happy Thanksgiving old friend.

From the UL White Book, the scope of Conduit Fittings (DWTT):



The same Category Code (CC) acknowledges "Some of these fittings are also suitable for use in certain hazardous (classified) locations where unclassied locations fittings are permitted in Articles 501, 502, 503, 505 and 506 of the NEC."

Then again, TMCX fittings fall under Category Code CYMX rather than PJOX with no reference to locknuts. I no longer have access to the UL standards, but I don't see a cross reference between the basic test standards, ANSI/UL 2225 (CYMX) of and 514B (PJOX) that would place a "locknut" restriction on TMCX fittings.

My position is that fittings that are otherwise acceptable in classified locations with 5, 4-1/2, or 7, threads engaged are also suitable [Section 500.8(A)(3), if necessary] to comply with Section 50x.30(A) depending on the application. [Note Section 50x.30 makes no significant distinction between Division 1 and 2.] Absent a specific prohibition in Section 500.8(E) or a Formal Interpretation to the contrary, I will maintain that position.

I was on a different CMP in the mid-90s, but I warned CMP14 that introducing Zones to the NEC would open a can of worms when Zone equipment started affecting Divisions. I actually proposed the forerunner of MC-HL through API to avoid Zones. The real purpose of "Division 0" or Zones was to reduce weight on offshore drilling rigs and allow lower weight IEC type equipment. The threading issues of Section 500.8(E) were introduced "harmonizing" NPT with metric threads.

So I have read and read into your statement and come up more confused than I started when I first read this. I don't want to try to argue the stance but try to understand why its ok in this instance but not ok in other instances. This all started by reading the article by EC&M, the one about EMT connectors and meyers hubs not being listed to be used together. Ran into lots of problematic installations in my eyes that this brings up since I started trying to make since of this, IE most of them stemming around RMC-IMC fittings for the most part only accepted to by used with RMC-IMC. So I can't understand how a listed weather tight EMT fitting being tightly installed is any different than 2 listed classified fittings that are not listed to be used together is any different? Seems like a double standard to me.

 

[rbalex]

No weight saved if you account for all the supports needed for MCHL unless you run cable tray everywhere and that's not practical on a old platform. Strut is heavy and supports every 6 feet is pretty fun when you could do it every 10' if you ran conduit. Also supporting 12" from a MCC is a really good time:happyno:.

I just tried to give you a bit of history. API has three "technical committees", Production, Refining and Transportation. I served on Refining's Subcommittee on Electrical Equipment (SOEE). API-RP500 is a joint document from the SOEE of all three Tech Committees.

In the early to mid-90s it was the Production SOEE that wanted an lightweight NEC equipment equivalent to IEC for offshore facilities. They pushed for a Division 0 and a heavily watered down Division 1. About a third of my career at that time had been for IEC projects. It was my Comment that was used to kill "Division 0" in the 1993 cycle. It's my opinion that after 20 years, still very few know how to properly classify loctions per NEC Zones. And mixing NEC Division and Zone installations is a recipe for disaster.

Originally, they wanted TECK90 as the cable alternate. In fact, most of your Alaska colleagues that come here want to know why we aren't using TECK90 in the US. It's acceptable in Canada for both Division 1&2. It's not accceptable in the NEC for either. You would have to ask UL why; I never got a clear answer, but they bought into what became MC-HL. I proposed it to my SOEE and they submitted it to CMP14. (I was still try to kill NEC Zones) They bought it and so did UL. (Personally, I like TECK90 too)

The current IEEE representative to CMP14, Will McBride, is from Alaska. I believe he's still on the current Production SOEE too. He has tons of North Slope and Alyeska Pipeline experience. Why not give him a call to find out his opinion of MC-HL. He's very approachable.

I'm from Alaska too (born in Fairbanks). My Alaska experience is more limited although I've sent twelve modules to Prudeau and designed the distribution for four production sites there. I also spent 2 years on ANSC. I had an Alaska PE until I retired four years ago.

 

[AKElectrician]

I just tried to give you a bit of history. API has three "technical committees", Production, Refining and Transportation. I served on Refining's Subcommittee on Electrical Equipment (SOEE). API-RP500 is a joint document from the SOEE of all three Tech Committees.

In the early to mid-90s it was the Production SOEE that wanted an lightweight NEC equipment equivalent to IEC for offshore facilities. They pushed for a Division 0 and a heavily watered down Division 1. About a third of my career at that time had been for IEC projects. It was my Comment that was used to kill "Division 0" in the 1993 cycle. It's my opinion that after 20 years, still very few know how to properly classify loctions per NEC Zones. And mixing NEC Division and Zone installations is a recipe for disaster.

Originally, they wanted TECK90 as the cable alternate. In fact, most of your Alaska colleagues that come here want to know why we aren't using TECK90 in the US. It's acceptable in Canada for both Division 1&2. It's not accceptable in the NEC for either. You would have to ask UL why; I never got a clear answer, but they bought into what became MC-HL. I proposed it to my SOEE and they submitted it to CMP14. (I was still try to kill NEC Zones) They bought it and so did UL. (Personally, I like TECK90 too)

The current IEEE representative to CMP14, Will McBride, is from Alaska. I believe he's still on the current Production SOEE too. He has tons of North Slope and Alyeska Pipeline experience. Why not give him a call to find out his opinion of MC-HL. He's very approachable.

I'm from Alaska too (born in Fairbanks). My Alaska experience is more limited although I've sent twelve modules to Prudeau and designed the distribution for four production sites there. I also spent 2 years on ANSC. I had an Alaska PE until I retired four years ago.

First I appreciate the history lesson and you gave great informing information. I do appreciate it. Second I am still unclear if I am right no matter how technical. I have been studying for my Admin. card and have been reading and studying for it part of this is reading electrical articles and forums trying to become smarter and better at my job. Like I posted earlier about the EC&M magazine article, when I read the article I researched a lot of stuff and found that common practices done here were wrong, technically. I have had the privilege of working with some very intelligent Electricians in my 10 years in the trade. Part of the learning experience given to me has been this is wrong redo it, and to think for myself. Great learning experience, with it some of it has been about listing. Like using a RE that isn't listed for classified use, fits the bill on the threads engaged but it was not listed so redo it, wrong is wrong right? But with that being said have also been told to do things that were not right but worked out with what we had. My whole point to finding out if I am right about this because if we all just follow suit and do it cause that's how we've seen it done. Seems very much like a slippery slope.
I completely understand how the whole AHJ thing works and what they say goes. Now with that said I refer to my point of just doing what you have seen before. Say someone only works in the oil and gas field and this is the only way you run MC-HL, then they go to do work in town and decide that MC-HL would work best in a gas station, then a inspector decides hey not legal redo it.
IF I am right it seems to me that it would be a very easy fix that would just cost a crap ton of money in testing, but why would a sales company do that if they could just sell two different systems of distributing circuits, and let people just decide to disregard what ever rules make a install cheaper. Like I said I have been wrong before and not afraid of admitting defeat so I can learn the ins and outs of UL listing book better cause its a new book to me.