Been having a debate with a mate this afternoon about a circuit in his house.
The circuit is a radial with 16 amp mcb that was previously used to feed his immersion heater that was removed when a boiler was fitted- he doesn't have a radiator in the conservatory and cant afford one to be fitted. he is going to divert the cable from his kitchen where the Cu is out the wall into the conservatory. Then get the electricians at his work to give it the once over.
He is of the view the way to wire a 3kw electric wall mounted heater in is to use a 13 amp FCU. I am saying no, have to use a DP 20 amp switch fed from breaker. 3kw is just over 13 amp 3000/230 = 13.04 amps and given the circuit is a radial fed with a 16 amp breaker with nothing else on it, the fcu is doing nothing of use and is un-necessary. Also adding 3kw heaters onto a ring will likely overload it.
This is the bit that then made me chuckle, he has recently been on a job - hes a surveyor for social housing outfit where the electricians have put 2 separate 3kw heaters on 13 amp fcu's joined to the rfc during refurbishments of some social housing units. He seemed oblivious to the issue of having a couple of 3kw heaters plus the other household appliances on the one 32 amp ring!
It makes you wonder how there haven't been more grenfell fires if the supposed people in charge of quality and standards sign off things like this. Of course given the low power draw of a lot of modern stuff its possible that the circuit might take the 2 heaters in the social housing example, but you don't know if the tenant will plug hoovers, irons and god knows what else in when the heating is on max.
The circuit is a radial with 16 amp mcb that was previously used to feed his immersion heater that was removed when a boiler was fitted- he doesn't have a radiator in the conservatory and cant afford one to be fitted. he is going to divert the cable from his kitchen where the Cu is out the wall into the conservatory. Then get the electricians at his work to give it the once over.
He is of the view the way to wire a 3kw electric wall mounted heater in is to use a 13 amp FCU. I am saying no, have to use a DP 20 amp switch fed from breaker. 3kw is just over 13 amp 3000/230 = 13.04 amps and given the circuit is a radial fed with a 16 amp breaker with nothing else on it, the fcu is doing nothing of use and is un-necessary. Also adding 3kw heaters onto a ring will likely overload it.
This is the bit that then made me chuckle, he has recently been on a job - hes a surveyor for social housing outfit where the electricians have put 2 separate 3kw heaters on 13 amp fcu's joined to the rfc during refurbishments of some social housing units. He seemed oblivious to the issue of having a couple of 3kw heaters plus the other household appliances on the one 32 amp ring!
It makes you wonder how there haven't been more grenfell fires if the supposed people in charge of quality and standards sign off things like this. Of course given the low power draw of a lot of modern stuff its possible that the circuit might take the 2 heaters in the social housing example, but you don't know if the tenant will plug hoovers, irons and god knows what else in when the heating is on max.
.
