new ring, RCD tripping

[JohnW2]

If that's the case John I will take the one peg off, it's now a radial circuit!

I'm not sure that it would achieve what you might hope. I'm not at all sure that changing a whole circuit from 1.5mm² to 2.5mm² cable comes within the scope (or, particularly, spirit) of 'replacing damaged cable' - so (although it's obviously a move in the 'safe' direction) it's quite probably still theoretically notifiable.

...and, before you get the wrong idea, I should point out that I'm not an electrician, so I have no axe to grind!

Kind Regards, John.

 

[EFLImpudence]

If you want to use a lower rated OCPD, then there would be no point in installing a RFC in the first place

Agreed. 433.1.5 and appendix 15 are for 'bog standard RFCs' without thinking. However, this does not preclude other configurations which comply with the regulations.

so a radial should be used.

Look at it another way - you are saying that if a 16A MCB is fitted then the return leg MUST be removed even though it is not doing any harm and is the equivalent (approximately) of using 5mm² cable.

I suspect what EFLI meant to say was "could be used" or "might as well be used", rather than "should (or must) be used". In other words, apart from 'unnecessarily' increasing the CSA from 2.5² to approx 5mm², there is no real point/advantage (other than the 'redundancy of an RFC, which is a mixed blessing) in having the return leg if the circuit is protected by a 16A or 20A MCB. However, as you imply, the existance of the return leg certainly does not do any harm - and, therefore, surely cannot be regarded as non-compliant?

Just to clarify - the quote "so a radial should be used" was from the post with which I was disagreeing.

 

[martinxxxxxx]

The regulation says that accesories may be supplied through a RFC protected by a 30A or 32A OCPD.

My version says:- A radial final circuit starts and finishes at the distribution
board, where it is connected to an overcurrent protective device.

Because I updated it with the
Corrigendum
(July 2008)
BS 7671:2008 http://electrical.theiet.org/wiring-regulations/updates/bs7671-2008-corrigendum-jul08.cfm?type=pdf

 

[Spark123]

A radial circuit doesn't start and finish at the distribution board though??
Thought the corrigendum sorted that out?

 

[JohnW2]

Just to clarify - the quote "so a radial should be used" was from the post with which I was disagreeing.

Whoops - sorry. I think it's fairly clear from my quoting and words that I realised it was RF Lighting, not you, but I typed 'EFLI' in error; I have corrected the offending post.

Kind Regards, John.

 

[martinxxxxxx]

A radial circuit doesn't start and finish at the distribution board though??
Thought the corrigendum sorted that out?

Well spotted

 

[acmedone]

It doesn't work like that, you can't do the work then get someone to certify it for you.

Eh? I just before I had a new CU fitted I laid the cables and sockets for a new ring. The electrician then tested the circuit and wired it into the new CU. Surely that isn't what you mean?

 

[EFLImpudence]

If you have been instructed what to do by your electrician and left for him to test before energising (as would appear) then that is a different matter.

The OP in this thread has done everything wrong, obviously energised the circuit without testing and then can't understand why it doesn't work, yet still expects to get someone to 'sign it off'.

 

[acmedone]

If you have been instructed what to do by your electrician and left for him to test before energising (as would appear) then that is a different matter.

The OP in this thread has done everything wrong, obviously energised the circuit without testing and then can't understand why it doesn't work, yet still expects to get someone to 'sign it off'.

OK. It would seem a bit silly if the regs demanded qualifications to crawl around the attic and drill holes in walls.