In the new Reg’s that apply from June 2015 there is more attention given to Auxiliary Circuits. As I understand it this applies to domestic gas/oil central heating control wiring and wiring accessories. For a 230V ac control circuit the detail of the new regulation 557 contains nothing but obvious common sense that a good electrician would apply anyway. However the new implication for domestic gas/oil (and maybe electric) heating situations is these circuits (often fed from a 3A FCU) are now defined clearly as “Circuits,” where the source/Distribution point commences at the FCU. So here is the main effect of this change, this control circuit is to be shown as a line item in the Schedule of Tests produced as part of initial verification. This of course means that initial verification as per BS7671 needs to be completed on this control circuit.
This has implications on electricians who install wiring for heating control wiring between thermostats, motorised valves and controllers. The electrician now has a few more tests and another line to put in the Schedule of Tests. What it means for gas and oil heating engineers is they will need to do the inspection, tests and schedule themselves or get an electrician in to do it for them.