Hi,
I have an electronics background so I understand the principles, and used to do my own house wiring before the regulations changed. I now employ an electrician, I'm renovating an old cottage, and we work side by side (I'll drill holes for him and he does the fitting etc). So all the wiring and CUs right back to the meter are all new and certified within the last 2 years.
I requested he run a spur for me from a ring main. Obviously better if I'd foreseen this as I had to rip out some decor, but it will be used to feed a heater I had not anticipated needing. This will be a 1.9kW clay core heater (hybrid storage/conventional heater). The heater supplier has specified this meets their regulations, in fact they often plug these heaters directly into a 13A socket. The ring main services two small rooms only (not the kitchen) and has bags of capacity.
My query is simply this: The electrician has used 2.5mm cable for the spur. The spur is only about 1m long, and I realise this is more than capable of feeding the 1.9kW load, but I expressed surprise because this won't be protected by the MCB which is 32A. It would have been difficult to jam 4.0mm cable plus 2 x 2.5mm into the source socket anyway. But he assured me this was acceptable. In fact on this website is says as much here
https://www.diynot.com/pages/el/el012.php#a0
As electronics professional looking in from outside, the regulations seem inconsistent to me. Is 2.5mm cable really OK? What is the reasoning?
I have an electronics background so I understand the principles, and used to do my own house wiring before the regulations changed. I now employ an electrician, I'm renovating an old cottage, and we work side by side (I'll drill holes for him and he does the fitting etc). So all the wiring and CUs right back to the meter are all new and certified within the last 2 years.
I requested he run a spur for me from a ring main. Obviously better if I'd foreseen this as I had to rip out some decor, but it will be used to feed a heater I had not anticipated needing. This will be a 1.9kW clay core heater (hybrid storage/conventional heater). The heater supplier has specified this meets their regulations, in fact they often plug these heaters directly into a 13A socket. The ring main services two small rooms only (not the kitchen) and has bags of capacity.
My query is simply this: The electrician has used 2.5mm cable for the spur. The spur is only about 1m long, and I realise this is more than capable of feeding the 1.9kW load, but I expressed surprise because this won't be protected by the MCB which is 32A. It would have been difficult to jam 4.0mm cable plus 2 x 2.5mm into the source socket anyway. But he assured me this was acceptable. In fact on this website is says as much here
https://www.diynot.com/pages/el/el012.php#a0
As electronics professional looking in from outside, the regulations seem inconsistent to me. Is 2.5mm cable really OK? What is the reasoning?