meter tails

[PGE SERVICES]

Hi I am a newbie and would not dare to say I am a spark! I am a plumbing and heating engineer but I have just completed Part P full scope and I am doing 17th edition next week. I am looking at putting a new CU in at home partly cos the one I have isnt 17th compliant and partly to go through the process of an NICEIC inspection. The on site guide says new meter tails should be 25mm2 and that came up in exams, however I have just realised that is CSA not diameter and this may seem a stupid question but how do recognise what meter tails are already in? I went on an online calculator and it said 25mm2 is approx 6mm diameter, but surely this cant be right to take 100 amps? Can anyone clarify please?

 

[steve-the-hat]

The conductor of 25 mm2 is about 6 mm in diameter, but with the double insulation the tails will be about 12 mm in diameter.

 

[Deleted member 9648]

The 6mm diameter I guess is about right for the conductor..minus insulation ,for a 25mm cable.....If your installation has not been updated in the last 15-20 years your tails will almost certainly be 16mm. Have a look at your DNO fuse,you may find it is a 60a, in which case 16mm will be fine,you only need to upgrade to 25mm if your supply is 100a. It is hard to give advise on visually telling 16mm from 25mm...a spark just knows from experience....but if you look closely at the insulation sometimes the CSA is printed on there