meter tails

[xxxpaulzzz]

looking at getting old 4 way wylex fuse box replaced. this is fed with i would guess 16mm tails. also a two way fuse box feeding an electric shower also fed by 16mm tails.
however, tails from the board fuse to meter look really small. would guess they may be single insulated but even so they look no more than 10mm.
i would guess a 10 way split rcd board would be going in. so 16mm tails must be ok as it seems pointless any bigger going in with such small csa tails from the fuse to the board. is this normal?

 

[riveralt]

Unless you intend to do this yourself, the electrician you hire would be the best person to answer your question.
25mm is normally the standard size meter tails.
If you do intend to do it yourself then your initial questions and constant guessing suggest that this task may be beyond your capabilities.

 

[xxxpaulzzz]

curiosity.....a burning desire to increase my knowledge....i have learnt so much from answers given in these forums.

 

[westie101]

Though it all depends on the copper equivalent size of the incoming supply cable, a dimension for which we are rarely asked.

As older supply cables can vary from
0.0145 to 0.06 sq in(approx 10 to 38 sq mm) other sizes being 0.01225 & 0.04
and modern ones from
16 sq mm copper to 35 sq mm aluminium (25 sq mm copper equivalent)

To suggest 25 sq mm tails are the norm might just be incorrect in some cases!

 

[EFLImpudence]

It all depends on the supply you require and/or may be given.

Also the fuse rating in the main cut-out. You cannot rely on any stickers or markings on the device. There could be a differently rated fuse inside.

Small premises 60A may suffice - 10mm² tails adequate.
Larger 80A - 16mm²
Large 100A - 25mm²

Some electricians will replace the tails with 25mm² as a matter of course today. Undoubtedly better but not always necessary.
You will still be left, as you say, with the original supply tails to the meter which are the responsibility of the supply company.