This is a more a question about rules/regulations than actual EE, but I figured this was still the best sub-forum. We are about to start renovating a house, and we will have to change a few things in the central heating system. One problem is that we somehow need to get a cable from the wiring centre (downstairs) to the boiler which in a cupboard upstairs. This is a volt free connection that turns the boiler on/off. Now, I will let an electrician connect and check everything that is live. But since getting this cable from the wiring centre to the boiler will be messy and time consuming I figured I might save money by doing that part myself (and again, it is volt free so there isn't any danger). However, I haven't been able to find any information about what type of cable to use, or even if there are any rules/regulations or even recommendations about this in the UK. Does anybody know? For a volt free connection I could from an electrical point of view just use whatever 2 conductor cable I wanted. But I figured I should use something with sensible colour coding etc. to make sure I don't violate any rules (I will obviously avoid any colours that could make someone belive that this is live cable). This will after all be a permanent installation in a wall.