Surface mounted box and air tight sealing of incoming wires.

I did build mine into my cavity but it was only a couple of inches into my 300 cavity so I put in 50mm cellotex in place of the 100mm of fibreglass batt across the back of the box.

I'm near Huntingdon. They wanted us to put the meter on the front of the house near the door. Our builder rightly refused in his words "to put a wart on it's nose" and put it around the side. He just went ahead installed the duct from the agreed point on the boundary to that location. I believe the only requirement is that the meter reader can get to it without a key.

We used a standard in the wall meter box BUT it backs onto a small cupboard on the inside so heat loss shouldn't be too bad. That cupboard houses things like the CU, Network cabinet, TV distribution amp, burglar alarm panel, DECT phone base etc).

Edit: I suppose it would also be easy enough to add internal wall insulation to the small bit of wall in my cupboard.

Posted By: TriassicOthers on here have put the cavity wall enclosure in the garage wall and then run the cable underground to the house.

Be aware that doing that can cost more in cable. The DNO can put normal cable in the ground (correct depth and with trace strip etc.) any distance to the meter, but after the meter you must use armored cable in the ground. We thought about putting the meter on the garage 50m from the house but the electricians talked us out of it and instead we have it surface mounted on the house but the tails to the CU come up into the house via a duct through the slab. They are very thick armored cables, the duct was only just big enough.

Somewhat ironically although we have standard cable in the trench to the house, we now have 50m of armored cable back to the garage in the same trench. Different rules for different parties. Look in the trench and the small cable powers the entire house while the big fat cable runs the garage door!

Thanks all, food for thought. An external cabinet sounds like the most reasonable alternative to an internal meter for my application. Build in a hockey stick for an internal meter and see if they can be persuaded to use it. If not make it a "U" shape to an external cabinet on the boundary (tortoise hutch?) and bring the duct from the boundary to there.

The workshop/guest quarters is the new building/would have the supply taken to it, then it'd run from there to the house on the basis that the larger loads (welder, machine tools, EV charging) will be in the workshop. Still don't want chucks out of the building fabric in the workshop/guest quarters though.

Currently I'm on a shared (loop through the neighbours cutout) single phase 60A TNS supply with a faulty earth (poor connection to lead sheathing on the neighbours side) that's being run as a TT supply using the incoming copper water pipe as the earthing spike. UKPN won't fix it - "not obligated to provide an earth" they say; can't convert to PME as you share a supply with your neighbour and his wiring is a house fire waiting to happen; could upgrade but you'd have to pay for the lot incl reinstatement of your neighbour's block paved driveway. The chap they sent to inspect said that the way around this is to request an entirely new supply (go three phase as it's only £100 more and useful in the workshop and for EV charging) then request a disconnection of the original supply; this way you'll both get a functional earth and not have to pay DNO rates for block paving etc. (disconnections come from a different accounting bucket)