Well, there is a new MC product on the market from Southwire which uses an aluminum bonding wire in contact with the outer sheath for grounding.

Just snip the bond at the end of the sheath where the wires emerge and slip the connector on and connect to box. Also can be used with box clamps.

Here is a link to Southwire...
http://www.southwire.com/processGetArticle.do?commonId=c3ad73cd00d7c010VgnVCM1000002702a8c0____

Anybody used this product yet?

Comments?

shortcircuit

Is it actually on sale yet?

I have not seen anything but pictures of it yet.

I doubt I will be using it as most all our jobs require a copper EGC.

While we often run MC in place of EMT with the engineers approval I will be very surprised if we get the engineer to remove the copper EGC specification.

Bob

iwire, illustrations on that site imply it's availible with a green wire in addition to the Al ground.

That would be $$$hospital$$$grade$$$MC$$$ for redundant grounding.

Did I mention? $$$$$

Bob

How is the new product different than AC cable? Sounds the same.

Edit, I just saw the chart in the link showing the differences.

[This message has been edited by Ron (edited 11-08-2006).]

The new stuff differs mainly in that the ground wire is aluminum, full size (for the ampacity), and separate from the jacket.

My own suspicion is that this is a product that is intended to replace both AC and MC. Don't be surprised if, in a few code cycles, the sections on AC and MC get combined, and the "normal" products are no longer made.

From what I've been told by an AFC (Southwire competitor) engineer, AC and MC cables are treated differently when it comes to listing.
AC cable has to meet pre-established specifications, and MC is subject only to performance testing.

AC & MC were under the same NEC Article (334) up until '78

While back a supply rep had some at the supply house - that was several months ago... From what I understand, they were still seeking approval for connectors for it to be approved as a ground path. Did they sort that out yet?

I guess I'm not a big fan of the idea because I've seen what can happen to other mechanical grounds on RMC, EMT, etc. I still always run a ground wire and bond (pigtail) to my metal boxes. Gounding is a safety issue, and I hate to think of what can happen as a result of loose or improperly installed connector. I've seen a lot of "solutions" and "time-saving" devices that have tried to circumvent a wired-in ground, but I trust none of them. IT's not worth the extra minute or two it might save. IMHO.

Bob:
I saw a few samples of this a while back...
Talked to a few guys on different sites that had the sample dropped off.

NO ONE seemed to have any interest. The #10 AL appeared to be a candidate for PITA award.

I do not see any advantage, nor did anyone else. And as above...what about the connectors??

John

Is this MCAP wet location listed?

Iwire...I haven't seen it in the supply house yet.I have seen samples of #12 MC and also #12 HCF MC.

The metalic sheath was wrapped tight. The aluminum bond was #10 and was not covered with the mylar wrap.

gfretwell...dry location only with THHN rated conductors only.

I too would fear loose connecters at juction points leading to high impedance grounding with its use.

shortcircuit

OK that makes sense. (dry only) I guess that means not damp either. My only real concern with this is losing contact between the bonding conductor and the armor. A bit of corrosion would do that. I suppose part of the testing included "aging" this wire artificially in some way. I also wonder about how varying lengths perform. If they are short enough the armor itself is the bond, longer lengths have plenty of coincident contacts with the armor. Is there a sweet spot where there are not enough contact points with the armor to create a good bond but the armor itself is too long to be a good bond? Just idle musing.

I understand they design new products and do testing but the real test is 5-10 years in the field. Aluminum Romex was the hot lick in 1970. It was the devil incarnate by 1975.

I am not sure of any grounding issue coming n the future.

This new MC grounds just like AC cable has for years only now the bond strip is bigger.

My only problem will be getting engineers to accept it.