Lighting circuits and borrowed nutrals

[Adam_hacks]

Hey folks, quick question for you all, when changing the consumer unit do youHAVE to split the upstairs and downstairs lighting circuits over two rcd's?

In the situation of the classic borrowed neutral on the landing light i usually re-feed it for a small charge. I would always look to do this but i don't want to be in a situation where i tell customers it has to be done for the regulations if its a choice for them to make if they want to pay it.

Hope this makes sence, i have spent ages looking in the regs and OSG, i just don't want to mislead people.

Thanks in advance, Adam

 

[Octopus]

Hum.

That would depend on how the socket circuit(s) are arranged. The last borrowed neutral I came across only had 1 socket circuit so I put both lighting circuits on one rcd and the sockets on the other.

 

[Guest112]

off the top of my head I'm not sure if you HAVE to split lighting and power to either side of the split boards or if it's just good practice??

nothing more irritating than borrowed neutrals...

 

[Octopus]

off the top of my head I'm not sure if you HAVE to split lighting and power to either side of the split boards or if it's just good practice??

nothing more irritating than borrowed neutrals...

Nothing says you HAVE TOO but you need to minimise inconvienience!

 

[Adam_hacks]

Thanks for the fast responses murdoch and peter, they have an upstairs ring and downstairs ring, so will be splitting them but what i dont want to do is

a) do a job that does not comply
b) misslead customers by telling them it has to be done

I would always advise them to have the nutral re-fed and would always explain why

 

[Guitarist]

I would explain to the customer that if the lighting is all on one RCD circuit and it operates, then they will lose all their lighting. If they accept that and advise you that they want it to be as such, then you are designing the distribution of circuits to your clients' requirements.



Edit...
I did of course mean same MCB along with obviously the same RCD

 

[onions1066]

We have a certain area we work in where this was common practice, the best way is to sort it the cheap way is to double the lighting up on one mcb,

 

[Octopus]

If its left "as is" a comment on the EIC is in order.

 

[onions1066]

As is I would code it as a 2. both on 1 mcb I would note it as an observation only

 

[Des 56]

I would go a little further than some of the comments made and say although there are millions of installations with an existing borrowed neutral install
When you change the consumer unit,if you dont alter the circuit,you should not leave that situation of the borrowed neutral and still use the 2 feeds

There would be the same potential for shock as before, when working on a supposedly isolated circuit,but "you" have worked on the installation and you being the electrician,you cannot leave it "as is"

They should be put on the same mcb
(Now,that solution will surely puzzle and cause the 1 mcb 1 conductor mob to self destruct) :banghead::53:

 

[Guitarist]

Definitely 1 mcb if you leave it with a shared neutral.
What I would just add is that I always check for this before I carry out a CU change, and therefore have always had permission to get it sorted before touching anything. I would advise everyone to do the same.
Half an hour with an MFT before quoting can save a whole load of hassle later on.

 

[Engineer54]

As far as i'm concerned it's a no-brainer, ...why install a dual RCD CU, and have both the lighting circuits on one MCB on one RCD?? The whole point of dual CU's is to minimise loss of all lighting or all power from a single point fault!! Get the shared neutral sorted at the same time as up-grading the CU!!

 

[telectrix]

now you've reminded me i've got to sort ours out on landing light. bugger.