Max length for meter tails?

[ASH2020]

I've got two flats to wire. The two meters are in a common hallway serving both. It's about 4 metres into each flat from the meter.
Do I:

1. Put each consumer unit in a locked box and give the key to the tenants?

2. Run long meter tails and put the consumer units inside the flats? I'm assuming that for this option I would have to put a breaker just after the meter.

I can't find anything specific in the 17th ed. but maybe I haven't looked hard enough.

Any thoughts gratefully received.

Thanks
Andrew

 

[RF Lighting]

It is usually limited by the DNO.

You would need to ring them up and ask, as it differers depending on who the DNO is, but often it is around 3 meters.

Personally I'd install a switchfuse adjacent to the meter / cutout, and supply the CU in the flat as a submains in 16.0mm² or 25.0mm² split con or SWA cable.

 

[oharaf]

I'd go with RF's suggestion.

however a 'friend' of mine has meter tails that are 8 metres long!!!!!

And the DNO connected them up!!!

Shipley, Rob round the corner from me and NO I didn't put them in for him

 

[ASH2020]

OK, never used split con. Is it much more bendy and how do you terminate it?
Andy.

p.s. I suppose the obvious answer to the previous is yeah but, no but yeah but, Sharons friend says her mate's got meter tails that are 16 metres long but I never seen'em so she might be lying,yeah.

 

[Softus]

Presumably, if you have an isolator/switchfuse, this nominal 3m limit applies to the conductors 'twixt meter and isolator. Since it seems commonplace in apartment blocks to run split concentric (or SWA, or whatever) from the basement up to each apartment's CU, there seems to be no arbitrary (i.e. non technical) limit to that length of run.

Is that right?

 

[RF Lighting]

Yup.

The 3 meter rule seems to generally apply to meter tails stright from the meter to their first termination point.

This is where the DNOs OCPD stops, and yours starts, so (in theory) any fault on the installation will take out your fuse and not theirs.