Use of an RCD

[Mark_Burgess]

Sorry to have been do confusing! This is work in progress which I am trying to make sure correct! As per previous posts by me I am new to domestic!

?????? still the same regs!!

 

[Darkwood]

Think on this occasion its a chat with the customer that is needed as you said you will do before we start deciding where to take this, its pointless debating all the options if customer ends up pulling the rug from under you, although it wont of all been in vain as you can approach the customer now knowing the options you have and i would use the nuisance tripping issue as a strong point explain to them the tenant will have to have 24hr access to the main fuse board in their house to reset the rcd if it trips at all times even when they are out and the only way you see around this is to change to a cable that has a protective sheath or surface clip or trunk it but then cable calcs would change,this should be enough to make them think of the options rather than discard them as too much expense.

 

[craig1000]

?????? still the same regs!!

Correct you are Mark it is the same regs ;-)
Maybe i should have worded it better, I am new to doing my own work i.e being responsible for design etc from the outset of the job. come from a commercial installation only background where I haven't had to worry so much about that side of things. I am new to it & learning always as im sure i will until i put my tools down for good. The point is I am looking at the regs & asking questions to make sure i get things right, i cannot do anymore than that & need to learn. I don't believe anyone just learns their way round the regs book overnight, & many things can end up being left to an individuals interpretation of them, i have had a few points like this discussed on here before.
thanks to all who have left constructive posts.

 

[craig1000]

After a phone discussion with the customer they do not want me pull a new cable in, be it an additional cpc or a new swa altogether. I shall be going there tomorrow to discuss in person but if they maintain this stance,what would the options be?
They have said they intend to remove the lock from the loft conversion door (this is internal & accessed through the house anyway) as they are new owners & don't intend using it for anything other than when having guests over etc.
Either way the cable as we know will not comply so if they wont have it altered can i record it on the sheet as done pre 17th existing works & change CU in garage & put the supply to loft on a 50amp rcbo or 50mcb covered by 63 rcd, this way at least both the cable itself whilst not conforming will still be rcd/rcbo protected along with the final circuits off the CU it supllys(loft). Other option would be to have it with no rcd protection & just a 50amp mcb & then add a rcd in CU in flat, protecting all final circuits of that CU(shower, ring & lights in loft) but not protecting the cable itself.

 

[telectrix]

as i suggested before. the existing supply cable was installed to a previous edition of the regs. and if you are leaving it as it is, then it should just be noted on your cert. the size of the earthing conductor could well be an issue however.

 

[craig1000]

Customer will not go for reinstalling cable be it a new sub main or an additional cpc.
As we know cpc is too small. What options do I have other than walk away?
Could really do with the work! Can i do CU change & upgrade & then put that circuit back on a 50 amp MCB & make a note on cert of the situation. I could put it on RCD side of split way main CU & then at least although the cable doesn't comply it & its sub circuits have additional rcd protection. Looked further into loft & its confirmed to be used by guests staying over & it is literally a room with a shower room, far from a self contained flat.
100amp main switch with 3 mcbs, 50 for shower, 32 for ring & 6 for lights.
Shower is only a 8.5kw so could reduce 50 to a 40. Realistically the load from that board is never gona get anywhere near the 50amp mcb i will put it on, shower ramped up maximum drawing full 40 amps all lights on & 3 twin sockets, which will have nothing more than a tv/dvd player plugged in & sockets realistically wont be on whilst shower in use. I know this doesn't comply & is in correct I am just trying to see if there is anyway I can do the job & note the bits that don't comply on cert. Any work Iv done /will do will comply other than the fact i have transferred the 16mm into new CU.

 

[telectrix]

at the end of the day, BS7671 IS NOT STATUTORY. if you make the installation safer than it was and leave it with the same level of safety as if you had complied with BS7671. then that's the best you can do. just make sure it's all documented, and that the customer refuses extra works as advised by you.

 

[robsparky1975]

You cant get better advice imho then tels above,if i was in your boat id do the same,do the work they want to pay for and test/cert etc and note down on the cert which part of the existing install that you have not touched but customer not willing to have extra works to bring it upto 17th edition,I have had a similar situation,we cant force people to have work done,give your sceme provider a call and see what they say.If we correctly fill out the comments box then we cover our own backsides.