tuckermot

can some one please correct me according to 17th you can no longer protect all your circuits by one rcd and you have to spilt your circuits with 2 rcds so down stairs lighting on one and upstairs lighting on the other or individal rcbos for each circuit.question is if i supply a second ccu in a out building and it has 2 ways protected by a rcd will this pass 17th as the rcd will knock lights out and sockets at same time

Shakey

quite specifically Reg 314.1

your sub-cu will be fine, presuming socket outlets and lights is all thats on there?

and you couldnt protect them all on one RCD in the 16th, nothing much has changed, just the additional RCD requirements have 'highlghted' something that has always been there

tuckermot

thank you shakey

Des 56

THE 17TH EDITION BOARDS CAN BE VARIOUS CONFIGURATIONS
The dual rcd seems to be the type thats taking favour with most people
In the 16th one rcd covering the whole of the installation was a deviation because it did not allow discrimination between say the lights and sockets
The 17th regulations require rcd additional protection for mostly everything in a domestic dwelling unles its surface wired,so the double rcd is being touted with up lights on rcd with down sockets etc and other configurations as well
It seems to me that the single rcd covering the whole of the installation was never no major problem(In fact I have this in my own home and its never been a nuisance as far as tripping everything off causing mayhem is concerned)
The 17th requirement will be a problem when adding lights and such to existing installations
How many people will use a double rcd for discrimination then (not many I would think)
So why the option of one rcd is frowned on by many is not a big problem in my estimation
Additions will be provided with one rcd where necessary and no thought given to discrimination in these cases ,so why do we be so concerned for new installs
Bring back the one rcd over the whole of the installation if thats whats wanted I say
and forget this dual rcd game of picking which team the up lights are on
Things are being over complicated with little advantage being gained


I take so long to type these essays out I get logged out
Getting more and more annoyed with this function lately

tuckermot

Thank you des
well written !!!!
i am impressed

Shakey

but what about the smokes Des?

Ideally they should not be on an RCD, but if the supply cable for them is buried, then they may have to be

so then they cant be on the same RCD as sockets

difficult to achieve with one RCD? Of course we could go RCBO, but that is to comply, and if we are goiung to comply the 314.1 applies

Had8Lives

Don't know if this would strictly comply, but if you installed an emergency light in the out building then there would still be light, even if the sub CU did trip.