On Sat, 22 Aug 2009 10:53:45 -0700 (PDT), NT
wrote:

If youre saying they're selling pvc flex as good for immersion heaters
it would be interesting to see.

This is what they say: "General Purpose - Pvc Heat Resistant Cables
Application: Immersion heaters, Storage Heaters, Radiant fires and
longer runs of low voltage lighting. Other applications that require
flexible heat resistant cable Not be used in areas where the cable may
come into contact with grease or oil. Current Rating: 16 Amps"

Short term pvc goes very soft, conductors migrate through it, and
fires tend to happen. Long term is hardens and falls apart
Rubber suffers no ill effect short term, long term it hardens and
breaks.

So rubber has benefits in the short term but long term prospects are
bad with either?

Of course overloaded or overheated cable has poor prospects, thats
what overheated and overloaded mean.


Sorry, I knew that, what I meant to say was the rubber has the
advantage of being safer in short term situations but you are quite
right, it shouldn't be overloaded in the first place.

BTW, how accurate are the thermostats? If set to 60C will I get 60C,
or 55-65C, or 50-70C, etc?

Last time I looked at specs for one it had huge hysteresis.

I'm best to set it to 70C then just to be sure.