Hi, just a quick question, I am changing the cable from my wiring centre to my boiler (it is 3 core) with a neutral, earth and a switched live wire. The previous cable has a slight nick in it so I want to change it. What size/type of cable is best? I was thinking of 2.5mm but this seems like flat cable and not round like the current cable. What type is best to use? Thanks for reading my question