Cable to remote CH motorised valve

[Philip Oldrosedene]

I wish to bring a remote CH motorized valve (Honeywell make) into use. It wasn't connected when the CH was installed as the valve was a last minute thought and no suitable cable was to hand. Up to now (8 years!) it has been left in the ON position.

Depending on route chosen, it will require 5 to 8m of cable to connect to the main CH controller. The cable into the valve is 5 way x 0.8mm sq (ie 1.0mm dia) - 4 control lines plus earth. The valve operates at

240V, so the cable needs to be rated for mains.

For preference I should like to use standard elec backing boxes to house the connections at each end, and bury the cable run under the wall plaster.

Please can anyone suggest a suitable cable & source?

TIA

[geoff]

In message , Philip Oldrosedene writes

Ah

Tha' needs some 5 core actuator cable ...

I have a reel of it somewhere, not cheap mind,

Try plumbcenter, but you might have to buy a 100m reel like I did

else, email me

[Dave Plowman (News)]

I'd be inclined to use two TW&E under the plaster and sleeve for identification then flex for the ends where it's outside the wall. Make sure the TW&E is properly protected according to regs.

Flex from any decent wholesaler or here:-

[Frank Erskine]

On Fri, 24 Jul 2009 14:18:34 -0700 (PDT), Philip Oldrosedene had this to say:

If you can't get hold of 5 core cable you could use 2 runs of 'smaller' stuff, provided that you clearly sleeve the conductors with divers colours to avoid confusion, and preferably document your choice of colours for future reference. (remembering of course to never use the ECC of a T+E for anything but a true earth, since it has no insulation - merely a sheath!).

[The Natural Philosopher]

use two twin core plus earth?

[Graham.]

Just use two runs of 1mm twin & earth. I don't know the layout of your system, but won't the zone- valve need to be wired to the boiler wiring centre rather than the controller? perhaps this is the same place in your situation.

Do you understand how the zone valve operates? The "4 control lines" as you put it are:- one pair for the actuator motor (designed to work permanently stalled) and the other pair is a micro-switch which closes when the valve is fully open, and calls for heat.

[Andrew Gabriel]

I have something similar. I'm using 5 core flex, which at the time was available in cut-it-yourself lengths from B&Q, but I don't think they do it in cut-it-yourself lengths anymore. (Actually, ISTR that I ended up with 6 core flex, as I think I had a spare core.) You can use flex for fixed building wiring -- it's just not normally done on grounds of cost and ease of handling.

At the actuator, I made up a suitable socket. I use the Bulgin

8 pin mains connector (often used for disco lighting). A panel mounted socket is cut into a standard blanking plate, which is wall mounted onto a flush back box, and the plug attached to the end of the actuator flex. Make sure the design of the heating is such that if the actuator is unplugged, nothing nasty can happen (e.g. boiler won't try to fire up with no flow through it).

[Dave Plowman (News)]

TLC sell cut lengths - and if you go to a branch no minimum charge. But I'd expect most decent wholesalers do too.