Standalone RCD?

[joojar]

I'm getting my kitchen ring main rewired, I've had a local professional sparky in for a quote and as expected the entirety of the new circuit needs RCD protection. However, the consumer unit will need upgrading (current unit is old-skool Wylex), and that leads to all existing connected circuits needing to be brought up to regs i.e. possibly the whole house will need a rewire.

So having digested all this, I got to thinking about doing the work myself (obviously with relevant notification/inspection via local building control). My aim is to do the work without disturbing the existing CU, there's a free slot on the CU to take an MCB for the new ring main, the thought I had would be to connect the new ring via a "standalone RCD".

It's not immediately obvious to me that this contravenes any of the regs, am I wrong? And does such a thing as a "standalone RCD" exist?

Cheers for any advice
JJ

 

[joojar]

Think I've got the details sorted now, my plan is: 6mm sq T&E from new MCB in unused slot on existing CU to new RCD enclosure. Had these in mind:

http://www.tlc-direct.co.uk/Products/MK5502.html
http://www.tlc-direct.co.uk/Products/MK5740.html

...and then the usual 2.5 mm sq ring main onwards from the new RCD. Sound OK?

 

[jason1958]

> leads to all existing connected circuits needing to be brought
> up to regs i.e. possibly the whole house will need a rewire.

Nope. Connected circuits do not need to be brought up to current regs.
- BR are not retrospective
- BS7671 is not retrospective

I can see 17th is likely to be grossly miss-used.

For a new CU to be fitted in PLACE of an existing one
1. Main Equipotential Bonding must be correct (job #1)
- this is a condition of electrical supply
2. Any existing faults (Code-1, Code-2) need to be corrected
- circuits have broken wiring accessories
- circuits have continuity faults
- circuits have Insulation Resistance (IR) fault
- circuits have EFLI fault
- circuits have TRS cable that is in bad condition despite passing IR test
3. Redesign started after 1-July-08 needs to comply with 17th regs re RCD
- ie, only after 1 & 2 can you start with the kitchen rewire

For a new CU to be added to an EXISTING one
1. Main Equipotential Bonding must be correct (job #1 before anything)
- this is a condition of electrical supply
2. Add kitchen circuit to that
- then rewire other circuits over time as time/money/redecoration permits

However, before you jump at the second option.
- FIRST STOP should be a PIR of the existing installation
- Only that way can you assess "where you are now"
- There may be serious defects requiring attention


Any failures on the PIR need to quote BS7671 regulations.
Rewiring a kitchen does not constitute refurbishment under BR.

If doing any work yourself, you need a good DIY book and then assess if you can do it or whether you just do the grunt work for a spark.