Switched Lives in Heating Control Wiring - sleeve or not? -

[aesmith]

Hi,
Quick question and hopefully not too silly. In the wiring for a heating system, is the convention to use Brown sleeve at on all cables that are either Live or Switched Live, where the insulation itself is not brown? Or only those where the existing colour might be misleading, like a Blue core carrying switched live.

Just thinking of the junction box where all our bits are wired, there are all sorts of wires which may carry 240V depending on the state of the system at the time aside. Off the top of my head there's permanent live to each zone valve (Grey), switched live back from each valve (Orange), switched live to the boiler (Dark Grey). Also the two outputs from the programmer whose colours I can't remember.

Thanks, Tony S

 

[James]

colours like red, yellow, blue, black and grey are commonly found in house wiring.
if any of them is going to be L, either permanently or switched, it should be sleeved with brown.

the short flex that is going to say a valve may have unconventional wire colours however, in my opinion they do not need to be over sleeved as the colour is there to show what the wire function is.

Ideally there should be a diagram on the valve or in the junction box showing the function of each of these cables.

 

[aesmith]

Thanks for the response. Following that principle do you also sleeve the wires on two-way switching? I've never seen that suggested, except when a Blue neutral is being re-purposed as a switched live. I had a quick look behind one of our light switches and none of the black or grey wires are sleeved.