Minimum distance between meter and CU?

Question

Right, decision taken, I'm going to change the CU before christmas for a nice shiny new one that will have plenty of spare ways for those circuits that I won't be able to install now, and with RCBO protection for the external circuits & kitchen along with a new non-RCBO circuit for fridges, boiler & freezers.

As larger enclosures don't cost that much more than smaller ones it makes sense to put the largest one that will fit in there.

I know the distance between the meter and the edge of the mounting board (where the current CU sits), but in determining the maximum size of CU that will fit in there is there a minimum distance between the edge of the CU and the meter that must be observed (and indeed a minimum distance between the edge of the CU and the edge of the mounting board)?

I also plan to mount a 2-unit enclosure with a 100A main switch in it to act as an isolator - this would have to be mounted below the meter. All tails, cables, etc will be routed in beautiful workman-like fashion, but any problems with this spatial arrangement?

Christian McArdle · Accepted Answer

Just keep the total length of tails below 2m and remember that technicallyyou aren't allowed to mount your consumer unit or isolator on the board atall.Christian.

RichardS · Answer

That's interesting - it's all on the same board at the moment! This is the board with the meter on, not the main service fuse - that's on a separate board altogether.

Meter tail length not a problem - they'll be about 60cm, pretty much the same as now.

Christian McArdle · Answer

technicallyIndeed, not a particularly uncommon arrangement, if not actuallypermitted...Christian.

RichardS · Answer

Hence my desire to do this now, whilst I'm still permitted without further inspection....

I reckno that if I change it now nobody will so much as raise an eyebrow. After 1st January, well who knows? If it's by the book then I'd probably have to get the electricity supply company out to remove, reduce size of and refit the board, create and mount another board, rebuild the entire meter enclosure and a whole manner of other work. So the cost might go from

Dave Plowman (News) · Answer

Think the reason is that technically the board belongs to the supply company as does the meter - you are merely renting them.

However, if they *really* didn't want anything mounted on it they'd use one of an appropriate size.

bob · Answer

WhyTheir is no maximum distance from the REC fuse to the Consumer unitdetailed in any Electricity Supply documentation.Bob

ARWadsworth · Answer

news:...The supplier may state the minimum cross sectional area and maximum lengthof the tails according to the OSG.Usually 3m length and 25mm^2 CSA with Yorkshire Electricity.Adam

Dave Plowman (News) · Answer

Years ago when doing this for some flats, the LEB insisted on MICC fromthe fuses to meter/CU.

Andrew Gabriel · Answer

LEB did a ~10m run of SWA in my brother's case. I was slightlysurprised they didn't install any type of switch/fuse.

Dave Plowman (News) · Answer

This would have been circa 1970.My house also has SWA from the riser in the cellar to the meter at the topof the stairs - and no switchfuse. It was also done sometime round about'70 - before I bought the house.But the LEB guy was adamant about the MICC - perhaps for fire reasons asit ran through other flats in places.

Minimum distance between meter and CU?

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