Bellwire alongside T&E in conduit

[telectrix]

spot on pete. 3 pints of theakstons, had to stay reasonably sober as i'm home alone apart from dogs. they need letting out for pees etc. from time to time.

 

[Mark42]

Hi Martin
Mains and control voltages are mixed up all the time in for example industrial control panels. It's routine. But rather than rubbish bell wire, why not use some oval double-insulated mains flex? Much better quality, thin, cheap, and easy to work with.
What you don't say is whether the control circuit is a simple switch, or some funky electronics box which might not like AC voltage induced on the control cable.
Cheers, Mark