ECN Forum Forums General Topics of the Trade General Discussion Area New MC cable?

I thought about posting this a few weeks ago, but never got to it.

One of the EC's showed me a piece of 'new MC', with the tag on it. Bare alum 'grd'. He wanted to use the 'bare grd' as the grd conductor for the circuit, & bond it to his boxes, etc.

After a quick look, I asked him how he was going to terminate the alum at the boxes, etc??

The look on his face was priceless!!!

Bare alum looked like a #10, but I can't swear to it. Have not seen this EC, nor the new MC since.

Considering the copper situation, it may be coming sooner then we think.

John

The southwire web site does say the bare ground is up one size. I am curious about the termination too. With oxidation in mind I can't imagine the incidental contact with the shield will work.

Btw, in cruising the web sites looking for this MC I saw a lot of whining about the price of aluminum too. It is still cheaper than copper. Nothing would surprise me.
The CPSC and that Inspect-Ny site still have a hard on against aluminum.

I've only seen a sample of this stuff. My boss brought sme back from a seminar a few months back. I'd have to assume it would most likely be used in hospitals or where an isolated ground is necessary.

You guys have me confused.

As far as I know we will not be terminating this AL bonding strip, just cutting it off like we do with AC cable.

I understand your practical answer Bob but MC armor is not suitable for grounding so we must be depending on the EGC wire. The bonding strip in AC is to shunt out impedance in long runs of armor. The EGC in MC must be that ground and it may not actually have that much contact with the armor on a short run.
I am still waiting to see the connector this stuff uses. Of course if you bring it into the box all we need is an Al rated lug. I see that as the best choice, perhaps a double so you can splice the "goes outta" EGC.
I'm sure, if this stuff is cheap enough, somebody will come up with the missing hardware within a price range that makes sense.

Greg the point of this new MC is that the armor will be a reliable ground path.



I found the article I read about this.

Here are couple of key parts.



The entire article which has a ton of info can be read here at the IAEI
http://www.iaei.org/subscriber/magazine/04_c/trainor.htm

Bob


[This message has been edited by iwire (edited 05-18-2006).]

Greg, as Iwire points out, the sheath of this new MC will be recognized as an EGC per 250.118 and will allow MC to be used in 517 applications.

Other than that, I don't see where it will take the place of AC or HCFC.

With the larger AL bonding strap along the length of the MC smart cable, verses the smaller strap in AC, I can't see how it will be any cheaper.

Granted, I do like working with MC better than AC or HCFC though.

Roger

Maybe I'm missing something, but I don't see how you could use it in a patient care area. Isn't the EGC bare? That would violate 517.13(B).

Also, given the choice between a 10 AWG bare conductor to work with (MC) or an 18 AWG bare strip to work with (AC), I would prefer the strip. Why would a person buy this???

On second thought, I guess you could use it for wiring luminaires above the patient care area and use 517.13(B) exception 2, ...but why?