25mm tails

[AndyPRK]

Out of interest, when did 25mm tails become the norm for new houses ?

and all service blocks/helneys made to accept 35mm tails without some ports designed for smaller?

 

[JohnW2]

Out of interest, when did 25mm tails become the norm for new houses ?

Is it necessary 'the norm, even now? The issue, I presume, is that BS7671 thinks that 16mm² tails are not big enough if there is (or may be) a 100A cutout fuse (but I think DNO's disagree).

Kind Regards, John

 

[RF Lighting]

To comply with BS7671, 16mm² tails do not have sufficient CCC to be supplied by a 100A fuse, especially if they pass from the meter cabinet to an internal CU, as the cavity wall insulation will reduce the CCC further.

Henley blocks have had ≥35mm² terminals certainly for the past 15 years.

The older ≤1970s DP henleys would take 2no. 25mm² tails, and 3no. 16mm² tails.

 

[Lectrician]

WPD, in my area, never fit more than an 80amp fuse in a standard cutout, even though they are labelled as 100amp.

For 100amp supplies they will always use larger cutouts. Not sure about the recently acquired WPD areas.

 

[EFLImpudence]

Out of interest, when did 25mm tails become the norm for new houses ?

I would hazard a guess that it was when people started believing the misinformation in the OSG.