Joint neutrals on lighting

[ultinator]

Hi. Up and downstairs have been interconnected in many places. RCBO's for each circuit won't work without re-wiring. Originally on 3036's. board been upgrded to RCBO's on all else. Is it better to a) put up and down on same RCBO? b) put both circuits into 6a mcb's so they are separate still. Or put an rcd to protect the two 6a mcb's in a desperate board?
there is no earth on any lighting, nor have i altered its wiring from when i arrived. So is it ok to leave un rcd protected so it stays as was or use an rcd to protect it?

id like to use and rcd to protect 2mcb's but there is only 3ways left in board(need 4 otherwise)

 

[cobrauk]

Well you shouldn't have done what you did in the first place until you tested the installation to check if it was OK to upgrade the Consumer unit, but if these circuits are interconnected they must be on the same rcbo as they have no earth advice getting rewired asap

 

[ultinator]

How about (due to space
constraints) one RCBO protecting 2mcb's to keep lighting separate?

 

[telectrix]

How about (due to space
constraints) one RCBO protecting 2mcb's to keep lighting separate?

hope you meant to say RCD there. easiest option is to put both circuits on 1 RCBO ( space is critical according to OP) but advise rewiring on your cert.

 

[ultinator]

Thanks for the kind words
i meant RCBO as it only takes one way in board. I was thinking of options. 3 ways left for up, down and rcd protection. So to have 2 mcb's one one rcd wouldn't fit. Unless u get 1 module rcd's. i know there's a reason but what would be the problem of using a 10a RCBO to protect to 6a mcb's. but really I was trying to kkeep circuits sseparate for convenience and do easiest thing is to put both lights on one RCBO? Also i didn't test this before hand as someone 'reliable' had and assured me just the sockets needed re-wiring. And yes I agree that is a stupid thing to do! Also re-wiring lights is too much for these people. And they have carpets about to gget fitted now.
Thanks again

 

[cobrauk]

You CAN NOT have two circuits that are combined some where in the circuit being fed from two Mcb's or Rcbo so forget even thinking about it

 

[telectrix]

exactly. if you can't split the neutrals, then tho only option is to put all the lights on 1 RCBO . it then becomes 1 circuit.

 

[dave274]

ultinator I don't want to sound rude but I think your a bit confused as to what an rcbo is used for, this is the impression I get from your post.

 

[GLENNSPARK]

How about (due to space
constraints) one RCBO protecting 2mcb's to keep lighting separate?

not on borrowed/shared neutrals you`d better bloody not...

 

[telectrix]

just wondering how a RCBO can protect 2 MCBs. i know i can fly to the moon, but then don't a RCBO be dedicated to 1 circuit, or has the law of physics changed since i last went away? p.s i got you all some cheese from the moon.

 

[GLENNSPARK]

just wondering how a RCBO can protect 2 MCBs. i know i can fly to the moon, but then don't a RCBO be dedicated to 1 circuit, or has the law of physics changed since i last went away? p.s i got you all some cheese from the moon.

it was just in case he had notions of using seperate MCBs sharing a common RCD for this.....

 

[Mr Mark Sparks]

Re no cpc

the nic have a sheet about this subject, basically it says do the job but put a sticker on the cu saying that no metal fitting are to be added to this circuit, that goes for cu changes where there is no earth in the lighting circuit.

It's also in esc best practice guide.

ill be back!

 

[GLENNSPARK]

Re no cpc

the nic have a sheet about this subject, basically it says do the job but put a sticker on the cu saying that no metal fitting are to be added to this circuit, that goes for cu changes where there is no earth in the lighting circuit.

It's also in esc best practice guide.

ill be back!

you mean the NIC actually feel they have to tell folk this?....
folk who are supposed to be `competant persons`?
its almost as bad as hearing TCs voice ringing out about the importance of Zs at these elex shows....

 

[Mr Mark Sparks]

you mean the NIC actually feel they have to tell folk this?....
folk who are supposed to be `competant persons`?
its almost as bad as hearing TCs voice ringing out about the importance of Zs at these elex shows....

12 whole pages of idiot proof guidance
http://www.niceic.com/Uploads/File1946.pdf

if link works

 

[GLENNSPARK]

link does work....just had a quick glance at it.....
load of patronising rubbish.....