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Meter Tails


binky

Question

If one has a small landlord's supply say max load 10A to run hallway lights connected directly to Cutout so 80/100A fuse, does one really need 25mm tails, or is it legit to use something smaller. The reason I ask is because I see quite a few mini CU on 6/10mm tails etc, and 25mm tails seems overkill, though I would argue that fuse is 80/100a therefore tails should match. Your opinions please.

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overload protection can be after the cable, so not a problem using 6/10mm to a DB if its only for a small load. although ideally, the main fuse should be replaced with a lower rating

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Main fuse can't be replaced as it serves a couple of flats. Out of interest then what size earth bond would you fit ? - if I remeber right it should be half the size of the tails min 6mm

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Main fuse can't be replaced as it serves a couple of flats. Out of interest then what size earth bond would you fit ? - if I remeber right it should be half the size of the tails min 6mm

you should still fit normal sized earthing

i dont think this is specifically in the regs, but if next door is TT, and they their main earth path is via gas/water pipes to your property and then to TNCS, you dont want a little earth!

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Not much danger of that on this installation, is part of a council group of small blocks of flats built circa 1670 on TN-s.

Was lookint at TNC-S property today, main supply cable looked tiny, more like 10mm than 16mm. Think its the smallest looking Split concentric cable I've ever seen, but then I suppose there isn't a seperate earth.

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Not much danger of that on this installation, is part of a council group of small blocks of flats built circa 1670 on TN-s.

Was lookint at TNC-S property today, main supply cable looked tiny, more like 10mm than 16mm. Think its the smallest looking Split concentric cable I've ever seen, but then I suppose there isn't a seperate earth.

you can get 4mm

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Before privatisation of the networks, the MEB (Midlands Electricity ) insisted on 25mm tails because of their cut-out fuse and would refuse to connect anything smaller. I think those days have gone now but really the tails are protected by the cut-out fuse, so if its 100a ...well what can I say.

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This is what I find odd, downstream of the CU we wouldn't dare use a fuse too big for the cable, yet for meter tails its ok?? Similar to supply flats from 80A Switch fuse in 16mm FTE - the earth is 6mm, yet that's OK. I never really understood how that is so?:|?:|?:|

what do you think you are doing when you spur a socket of a ring

32amp ring, spur off with 2.5 rated at 27amp

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what do you think you are doing when you spur a socket of a ring

32amp ring, spur off with 2.5 rated at 27amp

Well aware of this, but argument goes that demand wouldn't ever outdo the cable rating,2 x13A is only 26A which is the same argument for the tails and as for 16mm cable the Adiabatic equation applies. It just feels wrong.

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Before privatisation of the networks, the MEB (Midlands Electricity ) insisted on 25mm tails because of their cut-out fuse and would refuse to connect anything smaller. I think those days have gone now but really the tails are protected by the cut-out fuse, so if its 100a ...well what can I say.

This is what I find odd, downstream of the CU we wouldn't dare use a fuse too big for the cable, yet for meter tails its ok?? Similar to supply flats from 80A Switch fuse in 16mm FTE - the earth is 6mm, yet that's OK. I never really understood how that is so?:|?:|?:|

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