Adding RCBOs to Wyler Split Load CU

[cpvh]

Hi All,

I have a Wyler 12 way split load CU (NHrS12SL).

For various reasons, I will be having a qualified sparky do the work, but w anted to check my options...

Currently our CU has most of the power circuits on the RCD side, and 3 ligh ting circuits (which could maybe be reduced to 2 (combine the 2 downstairs circuits into 1 (it?s not a mansion). And the immersion is also on the non RCD side.

I am thinking it is time to give at least the lighting circuits RCD protect ion, but would like to avoid the cost of a new Box (which would allow 2 RCDs).

Could this be done by replacing the MCBs on the non-RCD side with RCBOs, an d could these be as slim as the existing MCBs? Or would it need the double width type?

Any suggestions as to which circuits to put where (without doing too much m essing, or we might as well go for a new box). Current setup is 3 power rad ials, one ring main, cooker and a spare 32 A (which might eventually feed a second mini ring for the kitchen) on the RCD side, and as noted above, 3 l ighting and 1 immersion heater on the Non-RCD.

[Dave Plowman (News)]

Generally, the more circuits the better. Can give you some at least working light when another fails.

I like to have the hall/stairs lighting on its own circuit. If that trips you can use lights from a room to see your exit, etc.

[John Rumm]

Any particular reason for wanting to change? Lighting circuits generally pose a very low shock risk, so the benefit from a RCD is limited for that application.

Wylex do single module RCBOs, so as long as there is enough height in that CU (RCBOs are taller than MCBs) you should be fine.

If I were adding anything, I would do a RCBO on the non RCD side for the kitchen, and leave the rest as it is.

[chrispvholmes]

The electrican who has been making ammendments to one of the existing light ing circuits saus that he HAS to put it on RCD in order for it to be regs c ompliant.

I wondereed about doing all the lighting circuits while I was about it. Wyl ex "say" that all circuts run under plaster should be RCD protected (well, they would wouldn't they), and if possible I'd rather not have all the ligh ts go out together, so a bunch of RCBOs on the non RCD side seems attractiv e.

Lighting circuits generally

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Cheers John

[tabbypurr]

hting circuits saus that he HAS to put it on RCD in order for it to be regs compliant.

ylex "say" that all circuts run under plaster should be RCD protected (well , they would wouldn't they), and if possible I'd rather not have all the li ghts go out together, so a bunch of RCBOs on the non RCD side seems attract ive.

I'm not sure there's any real upside to putting other lighting on RCDs.

NT

[Fredxx]

Interesting, this is an existing circuit and I thought an 'extension' or 'spur' was exempt from having to conform to the new regs.

Not that its a bad thing to move the circuit such it becomes RCD protected.

Rules now dictate that lighting must be split into at least two separate RCD protected circuits, so if one fails the other can still provide some lighting.

Wylex are correct for 'new' installations, where a cable is buried less than 50mm from a surface. Surface wiring does not need a RCD, nor wiring that is sufficiently mechanically protected, nor armoured cable.

[John Rumm]

Ah, ok did not realise you were altering the existing circuits. If making changes then yup they generally ought to be to the new rules.

(although I have at the back of my mind some guidance about this not being an absolute requirement for some instances of lighting circumstances - i.e. the requirement only takes force for significant alterations to the circuit)

They would, because they should. i.e. its not the fact that its a lighting circuit that matters, its the fact it has unprotected cables buried less than 50mm into walls.

Yup, you certainly want lighting spread over more than one circuit.

[Steve]

It can get interesting when the up and down circuits share a neutral, generally on the landing light.

[John Rumm]

Yup, although that in itself is a fault that should be fixed since it brings a shock risk all of its own.

[Steve]

Yeah, a Code 2 (page 14):

Often not discovered until you attempt to put the circuits on separate RCDs.

[Alan]

Wylex and Crabtree (Same Group?) have announced new 2 pole standard height RCBO's. There are rumours that this (2 pole switching) is going to be a requirement in the 18th edition, though there was no mention of it in the Draft for Public Comment when it came out. The Wylex press release also says something like 'adheres to new 18th edition standards.'

[ARW]

From that link

"Minimal descriptions such as ?poor?, and superficial statements such as ?recommend a rewire?, are considered unacceptable as they do not indicate the true condition of an installation. It will often be necessary or appropriate to explain the implications of an electrical installation condition report in a covering letter, for the benefit of recipients who require additional advice and guidance about their installation. For example, where an installation has deteriorated or been damaged to such an extent that its safe serviceable life can reasonably be considered to be at an end, a recommendation for renewal should be made in a covering letter, giving adequate supporting reasons. Reference to the covering letter should be made in the report."

My MD went mad when I put on my EICR just one word and that word was "Fucked". I considered that to be a true and informative comment of the electrical installation that the recipient could understand.

I was forced to rewrite the EICR.

My second EICR said "still f***ed and so dangerous that I am not prepared to test it"

The final copy - rewritten by the secretary removed the word f***ed.

When the landlord saw the final report he asked me "so basically this letter is saying the electrics are f***ed then?"

Always know your customer.

[chrispvholmes]

Thanks for that!, they look like they should do the job. And to (almost) answer your question, yes, I am pretty sure Crabtree and Wylex are both part of / owned by Electrium.

[ARW]

And a few others

Obviously made in the same factory

That also effected the Steeples MCBs (a Denmans rebadged brand) and the NewLec (a Newey and Eyres rebadged brands).

Nothing new there then

And one of my friends works at Carlton Bakery in Barnsley. Mr Kiplings cakes are the same thing as some other brands. They stop the production line and change the packaging.