Prohibiting MC Cable Use, Why?

[jtinge]

Some jurisdictions prohibit the use of MC Cable and manufactured wiring systems that are fabricated from MC Cable, even though they are NEC permitted wiring methods. Anyone know what reasons are typically given for prohibiting these wiring methods, especially if prohibited in commercial or industrial faciltities?

 

[iwire]

Some jurisdictions prohibit the use of MC Cable and manufactured wiring systems that are fabricated from MC Cable, even though they are NEC permitted wiring methods. Anyone know what reasons are typically given for prohibiting these wiring methods, especially if prohibited in commercial or industrial faciltities?

Yes, people in power placing their own feelings about craftsmanship and the 'good of the trade' ahead of any valid safety issues. In other words, we have to keep the boys working.


Obviously that is my opinion and not a hard fact.

 

[augie47]

Just a WAG but perhaps it's a carry-over from a time when many jurisdiction prohibited "BX" (the older AC with no bond strip).
That prohibition was on the books in these parts for many years. I don't recall which term the used (AC or BX) but any cable witha like jacket still draws attention.

 

[ken44]

I personally dont like the use it in commercial work particularly when leaving panels as most of my panels are suface mounted and this work tends to look unprofessional if not downright sloppy and often times the mc cable is not properly strapped-I could probably spend an entire day taking pictures of such installations. I have also had it blow up as I was moving wires around in a junction box because either an anti-short bushing was not used or the proper connector was not used. I have also had issues with multiple mc cable circuits not having a common tie circuit breaker-I have not pinned it down completey but the use of mc cable in general just seems to promote sloppy, non-code compliant work around here.

 

[iceworm]

Wow - interesting responses.
Following responses are based on my work is 99.99% industrial

I can absolutely guarentee that MC-HL (specifically) is a god-send here is the great north - far superior to any conduit system.

As for having the cables "blow up" when moving them in a cabinet - I don't know what to suggest.
Maybe, "Any wiring method, improperly installed, is a danger".

ice

 

[iwire]

As for having the cables "blow up" when moving them in a cabinet - I don't know what to suggest.
Maybe, "Any wiring method, improperly installed, is a danger".

I do not believe commonsense will be tolerated in regards to this subject.

 

[iwire]

I personally dont like the use it in commercial work particularly when leaving panels as most of my panels are suface mounted and this work tends to look unprofessional if not downright sloppy and often times the mc cable is not properly strapped-I could probably spend an entire day taking pictures of such installations.

Sloppy in itself is not a safety issue, should not be a code issue. Neatness should be between the customer and the EC. Banning a safe product for appearance reasons is wrong in my opinion.

I have also had issues with multiple mc cable circuits not having a common tie circuit breaker-I have not pinned it down completey but the use of mc cable in general just seems to promote sloppy, non-code compliant work around here.

How is the lack of a common tie circuit breaker linked to MC?


Wouldn't the better answer be to enforce the existing code sections and not ban an entire safe wiring method?

 

[iceworm]

I do not believe common sense will be tolerated in regards to this subject.

What was I thinking? I humbly and formally beg forgivness. :ashamed1:

Got to bail for a bit. I actually got a job this week - maybe six weeks worth. And this time ain't billable. But it is enjoyable.

later

The worm (in all humbleness)

 

[ken44]

A "neat and workmanlike manner" were a part of the NEC back when people took pride in their work, it seems as though things have trended the other way although I would not agree for the better of the trade and it all seems to spur around mc cable as I rarely here anyone debating over any other raceway the way that they do mc cable. I do agree that it has a purposeful use and I do use it at times and I do allow it use but there are times when I specify other raceways to the exclusion of mc cable, I was just saying that my personal experiences are what I described and they seem to come up negative more times than I care for.

 

[petersonra]

some places ban Romex and claim it is a safety issue, yet it is in tens of millions of buildings and there is no evidence it presents a safety hazard in any of them where it is used appropriately.

 

[iwire]

A "neat and workmanlike manner" were a part of the NEC

It is still in the NEC but the NFPA has put it in the list of vague and possible unenforceable code terms.

back when people took pride in their work,

I have a real problem with that as we run a lot of MC becuse that is what the customers want. The type of wiring method I run has nothing to do with my own sense of pride.

it seems as though things have trended the other way although I would not agree for the better of the trade and it all seems to spur around mc cable

The work belongs to the person paying the bill, it does not belong to the tradesmen, the designers, the engineers or the code.

As long as the work is safe all else should be up to the person or entity paying the bill.

But to each their own for sure and my opinions are no more important than any others.

 

[jtinge]

The reason for my original post is because for the last 25 years, we've had an unwritten policy that MC Cable shouldn't be used at our facility. However, no one that I've asked can provide the rationale for our policy other than that's the way we've always done it. There are valid reasons for being more restrictive than the code such as operational constraints, environmental considerations, experience, etc, but I like to provide the rationale behind any restrictions we impose.

I'm guessing our restriction on the use of MC Cable may be because we require all premises wiring to be installed in raceways with wiring installed after the raceways are completed. Another reason might be the fact that we required EGC's to be pulled in with the other conductors and original BX cable didn't have a separate EGC, but that's not the case with MC Cable. The third reason might be the perception that MC Cable in an industrial facility was less tolerant to abuse than the other wiring methods we used, and we extended the requirement to use raceways in all of our facilities regardless of occupancy or use type.

 

[Little Bill]

The reason for my original post is because for the last 25 years, we've had an unwritten policy that MC Cable shouldn't be used at our facility. However, no one that I've asked can provide the rationale for our policy other than that's the way we've always done it.

A little story along those lines....

A man asked his wife why she always cut the ham into before putting it in the pan.
She replied that was the way her mother taught her and he should ask her.

So the man asked his mother-in-law why she always cut her ham into before putting it in the pan. She also replied that was how her mother did it, and that he should ask her.

So the man wanting to get to the bottom of this went to the grandmother and asked her why she always cut the ham into before putting it in the pan.

She replied "well I never had a pan large enough to put the whole ham into!"

 

[jeremysterling]

A little story along those lines....

She replied "well I never had a pan large enough to put the whole ham into!"

Good call!

If you ask the original electrician at the OP's facility why MC is not used he will say, "The company never would buy me a rotosplit!"

 

[wirebender]

Good call!

If you ask the original electrician at the OP's facility why MC is not used he will say, "The company never would buy me a rotosplit!"

Or, "I hate getting my hands that dirty"

 

[petersonra]

I have been in plants that have strange requirements, or at least practices, that no one can explain but they have been done that way for a long time.

I suspect people are afraid to change because maybe there was a reason it was done that way 50 years ago that is not obvious. One place I put some stuff in many years ago required all conduit openings be sealed with silicone sealant. I thought this was messy and asked to use sealing washers instead. Eventually we ended up using the silicone. It was not worth the fight to me for a few dozen fittings.

 

[cowboyjwc]

When I was a facilities electrician, I liked conduit, because we tended to make a lot of changes or add to things. Sometimes it was nice to know that we could pull half way across the plant, sometime, and never have to run a lick of conduit.

 

[don_resqcapt19]

Yes, people in power placing their own feelings about craftsmanship and the 'good of the trade' ahead of any valid safety issues. In other words, we have to keep the boys working.


Obviously that is my opinion and not a hard fact.

You can trace some of these rules back to the fight between cable manufacturers and raceway manufactures, both looking to improve their bottom line via code rules. Even now, a lot of the proposals to require an ECG in a metallic raceway come from manufacturers of cable wiring methods. A lot of the proposals to limit the use of non-metallic cabling methods come from the metallic raceway manufacturers

 

[JDBrown]

The reason for my original post is because for the last 25 years, we've had an unwritten policy that MC Cable shouldn't be used at our facility. However, no one that I've asked can provide the rationale for our policy other than that's the way we've always done it. There are valid reasons for being more restrictive than the code such as operational constraints, environmental considerations, experience, etc, but I like to provide the rationale behind any restrictions we impose.

If only everyone were so rational...

A certain airport (which will remain nameless) where we do a lot of design work has a ban on MC cable but allows AC cable, and we've never been able to find out why. Go figure. It seems to me that MC having an actual EGC rather than just bonding via the metal jacket would make it more acceptable than AC, but maybe I'm missing something...

 

[iwire]

You can trace some of these rules back to the fight between cable manufacturers and raceway manufactures, both looking to improve their bottom line via code rules. Even now, a lot of the proposals to require an ECG in a metallic raceway come from manufacturers of cable wiring methods. A lot of the proposals to limit the use of non-metallic cabling methods come from the metallic raceway manufacturers

Don, I believe the OP was talking about local deviation from the NEC.