A very basic question about RCDs and regs 411.3.3. (i) (socket outlets) & 522.6.7 (cables in walls or partitions).
If a new 13A socket is installed on a spur on a pre 17th Edition (i.e. with no RCD protection) ring circuit in a domestic property, say in a living room, should the circuit be provided with RCD protection/RCBO or should it just be strongly recommended to the householder that RCD protection/RCBO is provided?
Whatever work you carry out must be to 17th Ed regs, i.e you need to provide RCD protection to socket outlet.
Now, there is a lot of conflict over how you achieve this, either to RCD protect the whole circuit OR just the work you have done, i.e the spur.
There will be many differences of opinion on this no doubt, personally as I have worked on that circuit I will endeavour to RCD protect the whole circuit, rather than just my extension.
Either way you must provide 30mA RCD protection to your work in this instance.
Undoubtedly the best solution, however as long as the existing circuit is not left any less safe than when you started AND your addition is to the 17th standard then all is well. I would still add to the works cert that RCD protection throughout is strongly recommended.
Its bloody tough sometimes trying to get over to customers that you would like to RCD an entire circuit that they have probably been using for years without any problems. You always seem to come across as a "sucking air sharply through your teeth" money grabbing sparky, not helped when John Wayne has undercut you!!!!!!!
If the circuit has no Rcd then when you come to fit an Rcd problems may arise
Our responsibility is for the extended circuit and the capacity of the original circuit for the addition
Rcd the lot ?
Rcd the extended bit ?
As said different views for many
If you decide to Rcd the extended circuit,the feed from wherever to the new socket/s also has to be Rcd or surface wired ,so I would say the Rcd has to be the first point of connection at the origin of the extension (next door to the original circuit socket)
I think I would just Rcd the lot and sort out any problems with the original
If the customer started muttering the negatives and is so little concerned with their own safety they may as well be givena wide berth and forget the job
It does depend partly on what the socket is going to be used for. If it's not for portable equipment for use outside the equipotential zone (building) , is labelled for a piece of fixed equipent and the cable you are installing is not buried then no RCD is required. Technically. Although theres no harm in making the circuit safer with an RCD.
The way I see it is you can NOT leave the installation in a state where it is less safe than when you started. In certifiying the circuit you are saying it is in a safe condition or giving guidance as to work to be carried out to make it safe.
As for paying for RCD protection I just explane that "an RCD will stop you getting electricuted where as an MCB will not" then go on to say that how the RCD is designed to protect people and MCB only really protects the circuit and property.
IT WORKS FOR ME LOL
I would protect the entire circuit but you are only responsible for ensuring your work complies and the existing circuit is safe to extend, ie that the insulation resistance is satisfactory,along with the R1 R2....Zs.. overload protection etc. To say that you immediately become fully responsible for the entire circuit is not realistic. If I add a simple spur to a ring main do I become responsible for the wad of connectors hidden under the floor by some other bod?
This is why you detail the exact extent of your work on the cert and that the test results were satisfactory.
But the whole circuit would be tested, not just the addition you have made. This means any problems with the original circuit might be shown up by the tests. You can't be held responsible for dodgy joints under floorboards etc as long as the test results show things look ok.
If test results show something is up somewhere (unsafe), are people saying that you could just test your new addition, as the original installation is no more unsafe than it was before you started? I can't see a note on the minor works form would get you out of trouble here if something happened.
Maybe the safest way to do things would be to quote everything "subject to satisfactory test results" and test the ring from a socket for continuity, insulation and earth loop before starting work. That way you know if you come across any problems later they're yours to sort out. This is what our place does, otherwise you get to the end of a job at 5pm, get the tester going and when you come across a dodgy result you don't even know if it's anything to do with your work or if it was there to begin with!
Re the RCD we would install all new additions to the 17th and as long as test results were ok on the circuit would just make a recommendation for it to be RCD protected and leave the final decision to the customer. This could of course be completely wrong but as there's conflicting information we've just used common sense. I'm not going to demand customers have to pay an extra ÂŁ100 for an rcbo on the circuit, otherwise they'll just get someone else in who doesn't demand that and think we're trying to rip them off.
Hi Cornburn,
No I wasnt implying that just the addition should be tested .Personally I carry out an insulation test on the entire circuit,at the DB, but continuity,and Zs tests I would carry out only on the part of the circuit I have extended. If RCD protection is at the DB the entire circuit would be RCD tested anyway.If the IR or RCD tests come up bad this could be a problem with the existing but would have to be rectified as it would affect the safety of the addition .
Reply to 17th Edition regs 411.3.3 & 522.6.7 in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
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