Hello, am bashing through house in preparation for a refurbishment including new thermal store and air source heat pump. Not sure of the final specs of heating as yet (investigating available green grants / schemes etc), but I'd like to route the required cables now. Guess sizing of ASHP would be about 12Kw (inverter type ~16-20A load) and thermal store would have at least two, maybe three, immersion heater elements which are back-up only or ocassionally used for when thermal store is completely depleted.
I don't mind oversizing cables or extra cost now for provisioning some redundancy, but don't want to have to bash through walls and floors again. So advice sort for the following:
1). New radial to ASHP location (well FCU inside wall behind future outdoor unit). 4mm2 T&E? As the heat pump will be running for many hours, oversizing cable to avoid losses etc seems sensible. Separate circuit, approx. 12m long and guess to 32A MCB?
2). New dedicated ring circuit for all immersion heaters. 2,5mm2 T&E? Back to 32A MCB or maybe new radial 4mm2 back to 40A MCB?
Wiring control centre for thermal store / UFH from a spur taken off existing ring circuit. Indoor ASHP unit down other end of house, also spurred from existing ring circuit, and the electrician can then run whatever Comms cables he needs to connect ASHP outside the house.
CU has unused 16A and 40A MCBs available, along with another two spare slots on the bus bar. All RCD protected.
I won't be making any connections, just routing the cables ready for a spark.
Any advice most welcome.
I don't mind oversizing cables or extra cost now for provisioning some redundancy, but don't want to have to bash through walls and floors again. So advice sort for the following:
1). New radial to ASHP location (well FCU inside wall behind future outdoor unit). 4mm2 T&E? As the heat pump will be running for many hours, oversizing cable to avoid losses etc seems sensible. Separate circuit, approx. 12m long and guess to 32A MCB?
2). New dedicated ring circuit for all immersion heaters. 2,5mm2 T&E? Back to 32A MCB or maybe new radial 4mm2 back to 40A MCB?
Wiring control centre for thermal store / UFH from a spur taken off existing ring circuit. Indoor ASHP unit down other end of house, also spurred from existing ring circuit, and the electrician can then run whatever Comms cables he needs to connect ASHP outside the house.
CU has unused 16A and 40A MCBs available, along with another two spare slots on the bus bar. All RCD protected.
I won't be making any connections, just routing the cables ready for a spark.
Any advice most welcome.
