Help with adding RCD protected circuit to old Wylex board

[CraigT82]

Hi All,

First off.. I'm NOT an electrician and am not about to commence DIY electrical work! Just looking to get clued up before calling a sparky out.

I'm having some work done on our bathroom which involves the fitting of Warmup underfloor heating and I've got an issue in that we have an old Wylex CU with BS1361 fuses. I understand that to comply with 17thEd the circuit that the underfloor heating is on to needs to be RCD protected (there is currently no RCD protection of any of the existing circuits).

I know the best thing to do is to get the whole CU changed for a 17thEd one but - after a bit of googling - I'd like to know if it's feasible to get a small garage consumer unit with a built in isolator switch, fit it with a 20A RCBO and supply it via a Henley block installed between the main supply fuse and current CU, and have the heating then connected to this RCBO as a radial circuit ( the literature for the heating states a 16A load).

Will the above meet current regs? Will a reputable sparky take this on? And if so can anyone give me an idea of the rough cost please?!

Thanks in advance for any replies.

Craig

SUPPLEMENTARY INFO: There are actually two CUs present... one on the E7 tariff. They're located in a store cupboard right next to the bathroom with plenty of wall space in the cupboard right beneath the CUs. There is one spare slot on the main (daytime tariff) CU. The installation dates back to 1987 and all lighting circuits have CPCs. I can't remember the last time we had a fuse blow.

 

[Octopus]

Without seeing the installation any advice on here is pretty much meaningless. Any work in your house needs to be preceded with ensuring that the earthing and bonding is installed and adequate.

EDIT: And this would be notifiable under Part P

 

[Meggerman]

Hi All,

First off.. I'm NOT an electrician and am not about to commence DIY electrical work! Just looking to get clued up before calling a sparky out.

I'm having some work done on our bathroom which involves the fitting of Warmup underfloor heating and I've got an issue in that we have an old Wylex CU with BS1361 fuses. I understand that to comply with 17thEd the circuit that the underfloor heating is on to needs to be RCD protected (there is currently no RCD protection of any of the existing circuits).

I know the best thing to do is to get the whole CU changed for a 17thEd one but - after a bit of googling - I'd like to know if it's feasible to get a small garage consumer unit with a built in isolator switch, fit it with a 20A RCBO and supply it via a Henley block installed between the main supply fuse and current CU, and have the heating then connected to this RCBO as a radial circuit ( the literature for the heating states a 16A load).

Will the above meet current regs? Will a reputable sparky take this on? And if so can anyone give me an idea of the rough cost please?!

Thanks in advance for any replies.

Craig

SUPPLEMENTARY INFO: There are actually two CUs present... one on the E7 tariff. They're located in a store cupboard right next to the bathroom with plenty of wall space in the cupboard right beneath the CUs. There is one spare slot on the main (daytime tariff) CU. The installation dates back to 1987 and all lighting circuits have CPCs. I can't remember the last time we had a fuse blow.

Yes, assuming earthing and bonding arrangements are satisfactory then seperating the supply and installing a small consumer unit and a new circuit would be one way to do it. If it is a small UFH system then a 13A RCD FCU may be appropriate spurred from ring final circuit. This would need to be determined by the electrician on the job.