ECN Forum Forums General Topics of the Trade General Discussion Area What is NMC?

Thanks Ryan, I am sad to say this particular job is not our work.

I was in this room for some other work and had to grab some pics.

Some of these feeders run hundreds of feet through suspended ceilings and where installed while the hospital was already up and running.

It had to be a real pain in the rear, this stuff bends about as easy as a solid copper bar.

Yeah we had a bit of a discussion on it here .
Them pictures are flash, Bob.
However, I've never seen Pyro bundled together like that before under saddles.
That could be a problem if the cables vibrate against each other.
I was always told to saddle them individually.
I did quite a bit of work with this stuff during my apprenticeship as an Electrician.
Anyone that thinks that this stuff is easy to work with needs to see a doctor.

Evening Mike, or is it mourning for you?


That could be interpreted as a NEC violation unless the saddles where non-magnetic.

NEC

Have you ever found the separate saddles warm or hot where used individually?

Bob

Gidday Bob,
Yes, I see what you mean, Eddy currents can be a worry.
Non-ferrous (Brass normally) saddles are usually used here.
BTW, it's Saturday afternoon here.

Thanks, Kale, for the info. What was your source? It probably has lots of other things I don't know in it!

I found this during my barn wiring method research...

"In the early 1930s when farms were being wired in great numbers, the only type of nonmetalic cable then made(now known as Type NM)was generally used in the wiring of farm buildings including barns.

It gradually became clear that the usual high humidity and corrosive conditions in barns caused quick rotting of the cable. The outer fabric jacket and the fillers in the cable acted as wicks, drawing moisture into the inside of the cable. With this deterioration came the danger of shortcircuits or shocks and fires.

It became necessary to rewire many farm buildings after only a few years because of the short life of the cable.

This led to the development of what was first called "barn cable",and which has now been standardized as Type NMC nonmetalic-sheathed cable. Later, underground feeder cable Type UF was developed.This too is suitable for wherever Type NMC(or Type NM) is otherwise used."

Seems that Type NMC nonmetalic cable was developed for barns and when UF was invented, it became the cable of choice leading to manufacturers of cable dropping it from production...

shortcircuit

reno:
The NM info comes from a little booklet I have from Essex Wire. The closest online resource I have found is at: http://www.essexep.com/electrical/techinfo/glossary.htm#n

The NEMA (National Electrical Manufacturers Assoc.) info is used without permission from the www.nema.org website. Search for RV 2-2005.



[This message has been edited by kale (edited 06-23-2005).]

See 334.2 Definition: 2005 NEC

Type NMC. Insulated conductors enclosed within an overall, corrosion resistant, nonmetallic jacket.


When someone finds this please post a picture or a link.

My bet still is that it is garden variety plastic NM with a plastic wrapper like MC instead of the kraft paper.

gfretwell, you're pretty close.

I had some in the basement from Dad's supplies.

It was virtually identical to the construction of UF, but it was a little more flexible, and had the uniform tan MN color we've come to know and love.

ETA: I remember finding lead jacketed wire serving my old outside porch light that dated back to the 1930's...

<minor hijack> anybody think the industry will standardize on the jacket color codes that are being sold by various makers?

IIRC, orange = 12 AWG, Yellow = 14 AWG ? <hijack>

[This message has been edited by DougW (edited 06-25-2005).]