meter tails

[Lectrician]

When changing a CU, the Tails must be 25mm, the main bonding must be 16mm

No they don't!! They have to have a higher current carrying capacity than the main fuse, so if you have a 60A main fuse then you can use 16mm tails and 10mm main earth!!

However fitting 25mm tails is good practice

16mm tails maybe, but not a 10mm earth

 

[sunsno]

OK, time to put this one to bed.

Lectrician & nozspark both quote that tails “have to have a higher current carrying capacity than the main fuse”. What page in the regs does it say that guys? I'm struggling to find it. I have read section 54 as Spark123 suggested but cant find it there.

I probably will use 25mm just to be safe but as a matter of principle I just want to see in 'black and white' where it tells me what I should do. Sorry if I'm being a bit thick here...

 

[securespark]

The days of regs that tell you what to do disappeared with the 14th. Ed.

The rule is :

In not less than Ib. In not to exceed Iz.

Look up the definitions in the regs - "SYMBOLS USED IN THE REGULATIONS"

As for determining size of the earth conductor, that's in 54.

 

[sunsno]

Thanks securespark. You were still as reluctant as the others to tell me exactly where in the book to find this but I have anyway. Its 433.1.1 on page 73.
So the answer is that with a 60A fuse 16mm tails comply with the regs. Whew, got there in the end.

 

[securespark]

Not reluctance. I didn't have the book with me & could not remember the reg no.

But you wanted to know, so I told you all I could.