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Joined: Jul 2004
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Since we a talking about obscure wiring methods is anyone using NMC? When I started looking at the wire manufacturers they shunt me off to UF.
My wild guess is that NMC is NM with a plastic wrapper instead of the paper so it would not wick up water but that is just a guess. I can honestly say I have never seen it and none of the supply houses I have visited stock it.
Greg Fretwell
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I also have never seen it. I have never seen NM-S either.
Ryan Jackson, Salt Lake City
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Joined: Feb 2005
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I believe the "C" designation refers to corrosive environments.
[This message has been edited by Larry Fine (edited 06-16-2005).]
Larry Fine Fine Electric Co. fineelectricco.com
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The C refers to the temperature rating of the cable.
Frank
Frank
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Years ago back in college, homework done, had a few hours to kill poking around in the engineering library. Found a book on electrical wiring codes (don't remember which book, it even might have been from Europe) and thumbed thru it. One wiring method described was "Mineral Insulated Cable". If I recall correctly it consisted of a metal pipe and two (or more) conductors. Insulation was some sort of high temperature material, which didn't like moisture. You needed special connectors (compression?) and white and black insulating tubing to slip over the wires so you could wire things up in a box (wires were bare away from the mineral insulation in the pipe). Also sealent to keep moisture out. Maybe similar to what is done with heating coils on electric cooktops?
Is this something that is obsolete, or is likely found in nuclear power plants or other exotic environments? Maybe a steel mill?
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wa2wise, please see the non-US forum for a discussion of "pyrotex."
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NM Non-metallic sheathed cable, braid or plastic covered. For dry use, 60°C.
NM-B Non-metallic sheathed cable, plastic covered. For dry use, 90°C.
NMC Non-metallic sheathed cable, plastic or neoprene covered. Wet or dry use, 60°C, and corrosive applications.
According to NEMA, "Types NMC and NMS are not commercially available, but type UF-B can be substituted for NMC. Type NMS is a construction consisting of NM-B and data/communications cables."
[This message has been edited by kale (edited 06-17-2005).]
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wa2ise regarding MI cable. Is this something that is obsolete, or is likely found in nuclear power plants or other exotic environments? Maybe a steel mill? Not obsolete in the least. It is commonly installed as feeders for emergency circuits. I saw a good video of it under test, it survived a couple of hours directly in a large (huge) flame all the while it was still conducting power just fine. Here is a photo of MI in a Hospital. And here is a close up of the connectors This is single conductor MI that is why you see it in groups of four phases A, B, C, and N. The brass plate is needed to comply with 300.20(B).
Bob Badger Construction & Maintenance Electrician Massachusetts
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Great pics Bob! I'm going to have to save those for some presentations.
Ryan Jackson, Salt Lake City
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Tom
Shinnston, WV USA
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