Guys, I was trying to explain to John (Renosteinke) in the Chat room last night about the cable we call Pyrotenax.
To give it it's correct technical name, it's called Mineral-Insulated, Metal-Sheathed or Mineral insulated Copper Sheathed.(MIMS or MICS)

It's a type of cable that is under-utilised down in this part of the world these days.
But I'm told it's still used quite a bit in the UK.
Considering it will withstand temperatures up to 250C (482F), this alone makes it ideal for fire protection circuits and the like.
Here is a guy holding a sample of the stuff:

[Linked Image]

This PDF file(331kb) tells you all you ever wanted to know about MIMS cables, even how to strip, terminate and fix this type of cable:

http://www.aeicables.co.uk/literature/mic.pdf

Believe me this isn't an easy cable to work with, it's rather finicky about being bent too sharply (just think Refrigeration piping) and the insulation inside the sheathing is very suseptible to moisture if the end of the cable is not sealed properly.
Keeping moisture out is important because the wires are bare inside the densely packed powder insulation.
There have been cases of this cable exploding, where a kink has been put in the sheath during installation of the cable and the sheath has cracked and it has gone un-noticed, until one day the cable fails.

{Message edited to re-size picture}

[This message has been edited by Trumpy (edited 05-31-2005).]