What diameter (inc. insulation) are 16mm² meter tails?
CU tails sizes.
- Thread starter Draughtsman
- Start date
It varies, but typically just over 9 mm diameter. 25mm² ones are not a lot bigger, at about 11 mm diameter.
Kind Regards, John
Thank you,
Mine would appear to be 25mm², at least, the new extensions to the original tails are. There's no text whatsover on the grey outer.
Mine would appear to be 25mm², at least, the new extensions to the original tails are. There's no text whatsover on the grey outer.
You're welcome - but bear in mind that 'it varies' (between manufacturers and even batches) and, with such relatively little difference between the ODs of 16mm² and 25mm², it's possible to make mistakes! Having said that, 16mm² is adequate for many/most domestic installations - despite the fact that it once become 'fashionable' to use 25mm² regardless!.
Kind Regards, John
My Vernier says the new 4m is 11mm dia, to the new CU after the Henley Blocks, with the original tails being about 2.5m. The cutout has a 60a fuse but that's just what the sticker says. So about 6.5m, meter to CU.
There is a lot of info out there saying 25mm² as standard but quite often it looks like it might be forward engineering.
Thank you.
There is a lot of info out there saying 25mm² as standard but quite often it looks like it might be forward engineering.
Thank you.
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Indeed, but I think that most domestic installations have either 60A or 80A cutout fuses, 100A being much less common - so 16mm² tails will be often/usually be fine.
Some would probably call it ('unnecessary') over-engineering!
Kind Regards, John
It is. Tails are subject to the same requirements as any other cable; i.e. dependent on the current and installation method.
Indeed - but the 'interesting' thing is that tails (or anything else) on the supply side of the meter sometimes seem to be subject to different 'requirements' from those on the consumer's side of the meter - and, sometimes, that t'other side may appear to 'a law unto itself'!
Kind Regards, John
Yes, the DNOs are a law unto themselves - not subject to BS7671, of course - using 16mm² for 100A.
Different physics, I suppose.
Different physics, I suppose.
Yes, it would seem soYes, the DNOs are a law unto themselves - not subject to BS7671, of course - using 16mm² for 100A. Different physics, I suppose.
To be a little more serious, it could be that DNOs (or the rules/regs to which they work) do not feel the need for as large 'safety margins' as those which are undoubtedly built into the likes of the CCC tables which we (BS7671) use - and I can even think of reasons why they might not feel that need.
Kind Regards, John
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