help specify new consumer unit

[pixeluk]

Hello all,

I’m hoping you can help me specify suitable consumer unit to replace the existing one.

The photo below shows the current arrangement.

existing supply and consumer unit

• pixeluk
• 25 Aug 2010
• 1

The incoming feed and main fuse box date from mid 60’s when the house was built. The house was extended in the mid 70’s and again in the mid 80’s and it seems that the extra wiring was squeezed into the original fuse box. The only exception was a feed to an electric shower and a double socket in the utility room fed from a separate isolator mounted under the fuse board.

I’m about to have a kitchen extension built and I presume the new wiring for this as well as the current kitchen wiring changes are going to necessitate a new consumer unit to replace the current original fuse box.

My fear is that the various vintages of current wiring around the house may fall short with the demands of a modern RCD protected consumer unit and that what has started as a kitchen extension may escalate into a more comprehensive house re-wiring exercise.

I certainly like the idea of separating out the current mass of wiring into individual circuits on a new consumer unit and should this expose a particular bad/poor circuit then look to address this.

Is it possible/allowable to have non RCD protected elements – e.g specific circuit for fridge/freezer or for a circuit that is borderline and would otherwise keep tripping an RCD.

Are there any recommendations for the consumer unit I ask the electrician whose doing the new extension wiring to fit. I’d ideally like something flexible to have as much control over the individual circuits as possible and hopefully RCD them all but have the option not to.

Finally as you can see, when the smart meter was fitted I foolishly didn’t have an isolator installed after the meter and ideally should have had the meter installed in such a way as to leave space for a new consumer unit.

What’s the recommended route to getting the meter moved 6” and an isolator switch installed – I gather there is a high risk of breaking the fuse in the PME if it is removed – can I ask EON (my regional company) to change/upgrade this or should I ask EON (also my supply company) to move the meter and install a switch? Presumably the electrician can’t just move the meter and do this without breaking seals?

Thanks in advance for any assistance/recommendations

Phil

 

[ricicle]

Your Electrician should ideally be a member of a competant persons scheme to enable him to notify the works himself.

He cannot move the meter but it looks like a new unit might possibly fit in the gap, if not below which would mean new tails from the meter as the henley block would be in the way.

A new CU also means testing the existing circuits and upgrading any sub-standard earthing/bonding arrangements, not just a straight swap and forget about it.

I should discuss this with the Electrican and let him decide on the choice of CU as his name will be on the paperwork !!

It is possible to have non-RCD sockets for F/Fs etc but they are subject to different wiring methods under the 17th edition of BS7671.

 

[1john]

Step 1 - instruct an electrician to carry out a Periodic Inspection Report.

60's 70's and 80's wiring, if installed properly should be servicable, but it is hard to know what state it is in, especially from a picture.

The ultimate installation in my eyes is one that used an RCBO to protect each circuit requiring RCD protection, with lots of circuits, if you would want your fridge freezer non RCD protected then certain cable or routing of cable needs to be considered and you shouldn't have a socket outlet on that circuit as all socket outlets require RCD protection, therefore you would have to resort to wiring the fledx of the fridge freezer directly into a fused connection unit or some other suitable arangement.

 

[ricicle]

all socket outlets require RCD protection, .

Not if said socket is labelled up for specific use only......

 

[1john]

all socket outlets require RCD protection, .

Not if said socket is labelled up for specific use only......

True. But whos to say the labeling wont be ignored. this is one of my gripes with the regs, my bad. Not that the situation has arrised for me personally, but i have always RCD protected socket outlets.

 

[Risteard]

all socket outlets require RCD protection, .

Not if said socket is labelled up for specific use only......

Although, of course, that is dependant on the wiring system employed.

 

[1john]

More to the point with the labeled up socket, who is to say it could be understood, infact given the large number of people who live in this Country that cannot read or write English, this label would mean nothing to them in the slightest.

 

[pixeluk]

Thanks for the quick replies.

RCD protecting (either grouped MCB or by individual RCBO) the new wiring for the new extension build and kitchen wiring changes goes without saying.

Also sounds like a separate RCBO for the Fridge/Freezer is the way to go.

However, for the current wiring that will be moved onto the new consumer unit – do I have to RCD protect all the existing circuits? Can I elect to use a split consumer unit with enough capacity designed for individual RCBOs but opt to have just a MCB on a circuit that would otherwise trip an RCD? What’s to stop swapping an RCBO for a MCB?

Obviously I’d like to get to the bottom of why an existing circuit is tripping an RCBO but can I elect to revert back to a MCB for that circuit if needed.

How far reaching do the regulations extend to exiting wiring, if no changes are being made other than replacing the consumer unit, because of requirements for new works?

I’m just worried that one job is going to lead to another job (£££) and I’d rather be clued up ready for discussion with the electrician and not get bullied into works that don’t need to be done.


Thanks again, Phil

 

[ban-all-sheds]

My fear is that the various vintages of current wiring around the house may fall short with the demands of a modern RCD protected consumer unit and that what has started as a kitchen extension may escalate into a more comprehensive house re-wiring exercise.

It might, but if it does it's because it's necessary.

Is it possible/allowable to have non RCD protected elements – e.g specific circuit for fridge/freezer or for a circuit that is borderline and would otherwise keep tripping an RCD.

It is, but there's no reason why a F/F should trip an RCD. As you say, just have it on its own circuit so that nothing else takes it out.

Your Electrician should ideally be a member of a competant persons scheme to enable him to notify the works himself.

That is true, but...

As ever, personal recommendations are always the best way to find a reputable tradesman, but if you're having to go ahead without much in the way of those, or references, don't put any store by registration itself - sadly it is possible to become registered with woefully inadequate qualifications and zero practical experience. You don't have to spend long here to see people cropping up who are registered and "qualified", but who are clearly seriously incompetent in reality and who should not be charging for their services.

You need a PIR, a new CU, and possibly a full or partial rewire. It's possible to become a registered electrician without ever having done any of those before.

It's your money, possibly lots of it, and you have every right to ask prospective tradesmen what their qualifications are. Just being listed here is not a good enough guide. No genuinely experienced electrician, with the "full set" of C&G qualifications will mind you asking - in fact he will wish that everyone was like you.

I feel sorry for people who have been misled by training organisations and (shamefully) the Competent Person scheme organisers into thinking that a 5-day training course, a couple of trivial examples of their work and some basic understanding of how to use test equipment will make them an electrician, but not sorry enough to agree with them trying to sell their services to Joe Public.

He cannot move the meter but it looks like a new unit might possibly fit in the gap, if not below which would mean new tails from the meter as the henley block would be in the way.

Or to the left? How much room is there? Some 100mm trunking running from the corner would sit above the meter quite nicely, and all the cables could be extended inside that.

But whos to say the labeling wont be ignored.

Can't be helped.

More to the point with the labeled up socket, who is to say it could be understood, infact given the large number of people who live in this Country that cannot read or write English, this label would mean nothing to them in the slightest.

Ditto.

 

[Steve]

The cheapest way to get that meter changed is to have it changed for a postpay meter. Theres no reason for a prepay meter if you can afford to build an extension.

Then when the meter man comes, make him a cuppa and get him to move it over. Before he comes, have an isolator fitted to the board with tails long enough to reach the new meter location.

 

[ban-all-sheds]

Moving it AND connecting to an isolator?

That'll be choccy biccies as well as a cuppa, surely?

 

[1john]

Moving it AND connecting to an isolator?

That'll be choccy biccies as well as a cuppa, surely?

Nah nah nah, bacon butty (although it doesn't have to be the posh bacon you are used to BAS)

 

[securespark]

(although it doesn't have to be the posh bacon you are used to BAS)

 

[bhm1712]

its not a prepay meter, it looks like a first utility smart meter to me.

 

[ban-all-sheds]

Nah nah nah, bacon butty (although it doesn't have to be the posh bacon you are used to BAS)

I only buy the posh stuff when it's reduced...