In an earlier contribution to this discussion,
Dave Liquorice wrote:

On 1 Dec 2006 09:30:43 -0800, Aidan wrote:

Screened twisted pair. Connect the screen to earth at one end only,
this is usually at the controller. There's usually only mA of current
involved with sensors, I don't know why 1 mm2 is needed.

Smallest cable that has mains rated insulation? I suspect that even
the "low voltage" side of the device is not fully isolated from the
mains thus any external cabling needs to be mains rated.

Donno if you can get mains rated screened twisted pair. Machine
control maybe?


ISTR that you can use telephone cable to connect the remote sensor on a
Honeywell CM67. Presumably the battery powered logic in this stat is
completely isolated from the mains side of the switching relay.
--
Cheers,
Roger
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