Domestic rewire, sanity check on CU siting

[Tim S]

Hi again,

Below is a bit of the floorplan of my house, ground floor:

the position of the meter box and another "meter" box next to it (the lower of the two green blobs, this contains the henley block and will have an isolator fitted and be the origin of the feed to the CU):

In the diagram, I really wanted to put the CU in position "D" - there's a

20cm recess in the wall which could be boxed in, loads of space, good access to roof voids and outside for SWA to shed etc. That's getting a new door, so I'd reverse the swing or make it an outwards opener.

But unless I want to throw money away but getting the service moved (>700 quid) or snake wrestling 25mm2 SWA (or split con) round the house, it's back to reality...

On the diagram again, positions A,B and C are *likely* to be able to meet the "3m" rules for running tails (EDF to confirm the exact length, just emailed them). Well, close enough, probably... The worst I've got to do if anyone complains it stick a switchfuse in.

Now: what I would be grateful for some opinion on are the implications of various CU sitings, partly in anticipation of the BCO who may or may not invoke bit's of Part M (it's not a new build, so I think I'm safe, but...) But also if there's a wiring reg concerning accessibilty of CU's - can't find one I admit, or anything else I might fall foul off.

Location A: Over door opening hard up against ceiling. Shortest meter tails run. Will be boxed in, effectively making the opening deeper.

Location B: Flush mounted into drywall backing onto roof void (this bit's good). Disadvantage, access is by climbing 4 steps up the stairs. CU would be at face height. I like this one actually, but I can see that the BCO or the PIR guy might object, just don't know on what grounds...

Location C: The lower left roof is becoming a kitchen/diner, so C is actually in a 300mm deep cupboard which will be set out to make it difficult to put crap in (looks like a kitchen cupboard because it's one of

4 in a row, but is the CU cupboard). Can;t see much wrong with this. Sinkl will be 3.5m away, bottom left bay, and cooker will be >1.5m away, left hand wall, so steam and heat shouldn't be an issue. However, it's got the longest "meter tails" run, possibly getting closer to 4m by the time they've gone up and down and round the bends (like me ;-> )

Thanks for your opinions in advance :) Yes I'm worrying again(!) but I don;t what to get the position of the CU wrong and be told to do it again...

Cheers

Tim

[jgharston]

That would be my prefered location, but slightly below the ceiling. Two of my flats have CUs like this. Does it have to be boxed in?

-- JGH

[Tim S]

Thanks for the reply :)

jgharston coughed up some electrons that declared:

I omitted to say it's an opening with a slight arch, so vertical space is limited. I *could* modify the ceiling in that region though, pushing it upwards at that point - that could actually work quite well, depending on the layout of the timbers in that region. Something to look at this weekend.

I think I would in this specific case, just for the mechanical protection. I'm thinking of someone carrying something tall and heavy through the opening and twatting the CU on the way past.

From the electrical design POV it's the place with least scope for whineage from either EDF or BCO's PIR bloke.

I wonder how the BCO would take to a full plans Part P submission... Wonder if anyone's ever tried?

Probably want certified engineering calcs for every run of every circuit...

Cheers

Tim

[Andy Wade]

Get the service moved then. Chances are that the cost will be forgotten in a few years time but a CU in the wrong place will continue to annoy.

132.12.

Too high, perhaps.

Access for testing etc. obstructs stairway?

Sounds the best to me, apart from the tails.

I think you do need to talk to the BCO.

[Tim S]

Andy Wade coughed up some electrons that declared:

That is a perfectly valid thought... It would be good because I can have a floor to ceiling wiring cupboard and I might be able to get a couple of bits of 40-60mm ducting presented there leading to a small pit outside which would make all further external circuits a total dream to install (plenty of room for SWA termination in adaptable boxes and no b***ering up the house up to do it). Apart from the cost (which was vaguely quoted by the dept who do the work, could be higher or lower) would be whether they would get "funny" about doing it to a LABC job, rather than me being a scheme member. There's a friendly sparks in the next town, I suppose I could just sub the bit of the job out - might be easier.

Do you know if they will do the whole job (install meter box, drill through wall, put "hockey stick" in and cable upto my isolator (I'll do the rest later) in or do they like all the prep done before they arrive, so they can just mole through, install head and meter and go home?

I would ask EDF, but my tolerance for phone calls to them is running low this week...

Thanks. OK just looked that up. The stairs could be argued against as one would be standing sideways on (one leg bent, other not, or balanced on one step). So there would be more of a tendancy to fall off compared to being on a step ladder. But kitchen cupboard is very good from this POV.

Reasonable interpretation?

True - step ladder involved to do anything much to it.

Noted above

Wish EDF would discover the joys of FAQs !

Totally agree. Would rather go to him with a reasonable plan though, rather than no clue at all. He'll probably be more amenable if I've made an effort first.

Thanks for such a comprehensive reply - totally appreciated.

Cheers

Tim

[Andy Wade]

You need to agree all that with them before they're due to turn up. The more donkey work you can do the less it will cost. Here's a recent thread on the IET wiring regs forum with a lot of relevant information:

an older one about hockey sticks 'The Wanderer' might be able to help here by suggesting how to keep the cost down and make the job go smoothly.

Probably.

Communication doesn't seem to be strong point in the new market driven supply industry... AFAIK though, no-one will accept tails >3 metres and some DNOs have lower limits.

A short list of options could be a good starting point though.

[mike]

Gawd - sorry, but this country is totally bananas - red tape and regs to the point of madness. Is there a red-tape industry I can buy shares in I wonder. Folk actually seem to revel in this over-red nonsense. Please no lectures on, "otherwise we'd all be electrocuted in our beds" cra*. Send any such junk to former waste of space highly paid egg-target Prescott.