Could any one please clarify for me the following. If I was to extend an existing ring main by adding two D/G sockets, with cables less than 50mm into the wall on a circuit with ADS but no RCD. Under BS 1671 would I need to add a RCD to conform to the Regs. Thank you. 

Yes you would.

you could just add it to your bit that you are adding if thats possible but obviously better if to them all

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Specialised Subject. The Bleedin Obvious. John Cleese

Not necessarily.
The requirement to provide RCD protection for socket-outlets only applies to those used by ordinary persons and that are intended for general use.
If the socket-outlets are not to be used by ordinary persons, or are intended for specific items of equipment, there is no requirement to provide RCD protection.

With cables concealed in walls, additional protection is required.
RCD protection combined with running the cables in prescribed zones is one method.
However, if the installation is under the supervision of a skilled or instructed person, RCD protection is not required.

I'll clarify my above post so as not to confuse the OP. If he is talking about a domestic installation an rcd is required.

Gary

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Specialised Subject. The Bleedin Obvious. John Cleese

BS 8436 cable is another option for concealed cables that wouldn't require 30mA RCD protection - which might be an economic alternative to RCDing the whole circuit especially it it involved a CU change. If the sockets were for general purpose use, RCD sockets might still be cheaper than a new CU (and provide better discrimination).

More than one way to skin a cat!

- Andy.

The SRCD option mentioned would be most efffective way of complying or just RCBO the circuit if the con unit is capable of the upgrade.
Regards
Antric

What about the new cable supplying the sockets? If less than 50mm blah blah. Perhaps an RCD protected spur could be used.

Regards

Only problem with RCD FCUs, is that the manufacurers' do not consider them suitable for fixed wiring.
I know that the manufacturers' instructions only need to be taken account of.
However if the manufacturers' are stating their equipment is not suitable for a particular use, is it something that should be ignored?

Point taken.I am starting to lack as I approach 50

That sounds a bit daft Spin, do they expect it to be connected by plug and socket then? I've fitted plenty to fixed wiring,

Dave.

Sorry spin, I'm with Dave on this, please explain further?

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Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!

The BEAMA handbook has a table indicating what use each type of RCD is intended for.
Some have ticks for fixed wiring some such as the FCU RCDs have crosses.
My understanding is that they are intended for the connection of a single item of equipment or appliance, to provide additional protection just to that item of equipment or appliance.
Here's a link:http://www.beama.org.uk/downlo...-4816-87188608E386D98D Page 26.

Which manufacturers for RCD protected FSU's?

Regards

Blimey!!! all my connys in North Manchester are not suitable if this is correct but I doubt it.CPN instructuions dont say anything about not using in fixed wiring.
I ll not be able to use my van tyres on the road next (Sorry Spin,couldnt resist it)
Regards
Antric

He''s been in the trenches too long, now suffering from shellshock.

Regards

The second page has a list of the manufacturers that I assume the information relates to.
There's also a list of the other organisations who were involved or contributed to the guide.
Make of it what you will.

Thanks for posting that Spin - it looks like a very interesting document!
- Andy.

But it also says that FCURCD is 'Suitable as an Outgoing
Device on a CU, DB,PB or SB (5,7)Part of the Incomer'
and
Ok for Protection to Socket Outlets 20A or less

wouldn't these include fixed wiring ?

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lomasjs

Does seem a bit contradictory doesn't it.
I can understand how an RCCB or RCBO can be used as an outgoing device from a DB/CU, but how an FCURCD would be so used is a bit of a mystery.
If it's acceptable as a method of protection for socket-outlets, then yes, one would expect it to be acceptable for fixed wiring.