Air Source Heat Pump Signal Flex

[Dan59H]

On Air Source Heat pumps there is a signal flex going from the Pump all the way to the Cylinder,
It's 0.75mm Flex and I'm getting two opinions about whether it can be run in containment (YT2 and 20mm conduit) with the feed.
The spark is saying that it can on 5Kw pumps (2.5mm T&E for the feed) but not 8.5Kw (4.0mm T&E) and the designer is saying because of harmonic interference that it must not be touching a live feed at any point on the run. Which is nigh on impossible to achieve except cosmetically.

Any thoughts?

 

[Justin2211]

Generally you should keep them apart in all cases but if there are not options other than to run them together your signal cable should be a screened cable to reduce any interference

 

[Marvo]

You should be able to get YT2 as a split trunking which would satisfy separation requirements. Conduit is a different matter but as Justin says if the cable is screened it shouldn't be a problem.