No pics sorry............

[Baddegg]

Went to view a kitchen refit this week, new kitchen and new rfc circuit dedicated to the kitchen, have a look at the CU and whilst inspecting I see that the 2 lighting circuits, up & down, are both wired with the same 1mm 3&E cable (pre 2005 cable)
Red as line to down mcb, yellow to up mcb, blue to neutral bar and earth to earth bar,
I am relatively new to this game but I’ve never seen that before and the customer says she’s never had any problems with it,ask for any old paper work and the cert (won’t mention the scams name) for a CU change doesn’t mention it but then it also says all IR readings were perfect ha ha!

 

[Baddegg]

Boil in the bag politicians?.........

 

[Baddegg]

Boil in the bag politicians?.........

 

[buzzlightyear]

op ,may be you should ring your scam .and maybe they could give you the answer . in which I am not knocking you., that the first place of call .

 

[Baddegg]

Thanks buzz,I would ring my scam but I wanted the opinion of electricians first!

 

[johnduffell]

Well it's good that at that has been aired out in the open! Anyway although I'm sure the neutral is wrong to be like that, I I'm less clear that the cpc has to be separate. As long as it checks out for adiabatic and ccc which it will almost certainly then it would be ok if it were a 4c+e wouldn't it? Anyone know if there's a reg preventing it?

 

[The Ghost]

The OP has stated he is qualified and experienced within the area of domestic wiring and has acknowledged that there are higher levels of knowledge and experience. I see no need to castigate the OP because that is his exlusive experience and skillset. Bear in mind you "real" electricians if put in a house and asked to rewire it would probably make a pigs ear out of it. If there were no such people then you real electricians would have to do all the house bashing which you would not want to do. So there is a gap in the market. House rewires are really not the complex end of electrics we all know it. Nevertheless it has a place. Really speaking there is no advice to give. Whoever did the wiring was wrong in the way they did it. I would advise the customer to get the person back to rectify it.
But that aside your question has been answered @paullyons in that you would note the problem on the certificate. Clearly there is a borrowed neutral which can lead to the situation of isolating one circuit and the potential for being electrocuted while beleiving it is dead. Personally I would not work on such an installation, without the owner allowing rectification of the problem or getting the person who did it back to sort it out.

 

[Baddegg]

I think I speak for a lot of boil in the bags here when I say that yes it is considered the lower end of electrical work with regards to skill set and knowledge but it doesn’t mean we don’t want to do it safely and properly,thanks vortigern well put!

 

[westward10]

It is an unusual thing to do and yes they can share a cpc but not the neutral, theoretically it could overload if two 10A protective devices are employed. It is possible this cable is jointed to existing cables at some point.

 

[Baddegg]

2 x 6a mcbs and dual rcd board both lighting circuits on same rcd though...

 

[Wilko]

Hi, my 20p view is - its one circuit with one N and one CPC that's (incorrectly) fed by two OCPD. This may give rise to danger in maintenance situations. While it's not pretty, an improvement might be to reduce to one OCPD. But this creates a division of circuits problem, so I'd rewire it.
Edit - just read they're on the same RCD (as they'd have to be) so reduce to one OCPD .

 

[Pete999]

I think I speak for a lot of boil in the bags here when I say that yes it is considered the lower end of electrical work with regards to skill set and knowledge but it doesn’t mean we don’t want to do it safely and properly,thanks vortigern well put!

Domestic work, is as has been said an art, it's not just the electrical side, you have to deal with customers on a daily basis, the problem solving may not be as dramatic as say Commercial or Industrial work, but there are problems regardless, how to route cable runs, how to avoid damaging decorations, how to plan the work especially when doing lived in rewires, without panicking at the end of the days work, trying to leave the customer, safe and sound until you come back to resume work the next day.
I have no recent knowledge as I am retired, but from seeing, and hearing some of the horror stories, regarding "boil in the bags", it saddens me, there are of course some very good DIs, but allied to that there are some real Cowboys, charging people good money for sub standard work, rant over sorry if it's old hat.

 

[Octopus]

Both at the board ..... needs investigating imho ....

This IS the answer to the OP ............ unless its investigated no one will have a clue.................. least of all people on a forum.

Your "later" declaration of that its a dual board, with both circuits on the same RCD, but separate MCB's ......................... well, the most obvious answer here is to have both "feeds" on the same MCB ........... then safe isolation IS achieved.

 

[shaun1]

Asside from the safety issues mentioned, it seems a bit pointless to me to wire it this way. There must only be around 5 meters of this 3 core to the first light in the dowmstairs circuit, then a split to some 2 core to run upstairs. So they have maybe saved 5 of meters of cable but the 3core is twice the price anyway.

 

[Toneyz]

deleted.brain not in gear yet.

Well it is Sunday Tel.

 

[Toneyz]

Domestic work, is as has been said an art, it's not just the electrical side, you have to deal with customers on a daily basis, the problem solving may not be as dramatic as say Commercial or Industrial work, but there are problems regardless, how to route cable runs, how to avoid damaging decorations, how to plan the work especially when doing lived in rewires, without panicking at the end of the days work, trying to leave the customer, safe and sound until you come back to resume work the next day.
I have no recent knowledge as I am retired, but from seeing, and hearing some of the horror stories, regarding "boil in the bags", it saddens me, there are of course some very good DIs, but allied to that there are some real Cowboys, charging people good money for sub standard work, rant over sorry if it's old hat.

Sumed up very well there Pete each skill set or niece of electrical work has its own set of skills although we are all putting in rings and radial circuits. The problem with these short courses is they may cram in everything academically with a limited practical but it doesn't replace a longer term on the job training. The OP will encounter these problems of existing installations on most occasions this is where experience & training comes in. How do you think the likes of Pete,Tel and even myself got over these issues before all the schemes helplines and internet forums.