100A DP Isolator Installation Between Meter and CU

[Midwest]

My experience regarding the length of the ‘tails’ with the DNO is basically “we don’t care”

I'm shocked. I'm always very careful measuring the run of the tails. Fingertip to opposite --- (1metre).

 

[Octopus]

Murdoch, does it not specify in BS7671 that all supplies must now be 25mm regardless?

No - but the "pretty" pictures in the OSG do suggest this is the case.

When I do a CU change I carry 25mm tails, 16mm GY and 10mm GY and the appropriate Henley blocks and MET's - then I can cover each eventuality....

If its a new build I certainly would fit 25mm tails.

 

[mhar]

The alternative to 'upgrading' the tails to 25mm is to ensure that the fuse does not exceed 80A.
What supply do people think they get these days? Halfway down this page Western Power Distribution - Information for electrical installers - https://www.westernpower.co.uk/Connections/Information-for-Electrical-Installers.aspx is the specification for a standard WPD supply (albeit one that needs one letter inserting).
Does the size of the supply vary accross dnos?

 

[Percyprod]

Working for dno, meter tails governed by rating of cu, NOT supply fuse. 100amp cu=25mm tails.

 

[static zap]

.......careful measuring the run of the tails. Fingertip to opposite --- (1metre).

May have to re-calibrate for "Moob-droop" !

 

[Ian1981]

Working for dno, meter tails governed by rating of cu, NOT supply fuse. 100amp cu=25mm tails.

Domestic consumer unit Main switches are rated upto a maximum rating of 100amp , does not mean you have to be using 100amp as your maximum demand.

 

[Ian1981]

Working for dno, meter tails governed by rating of cu, NOT supply fuse. 100amp cu=25mm tails.

Domestic consumer unit main switches are rated upto a maximum rating of 100amp , does not mean you have to be using 100amp as your maximum demand.

 

[Deleted member 26818]

421.1.201 as everyone knows requires the enclosures of CUs and similar switchgear to be made from a non-flammable material (essentially metal).
However 421.1.201 also requires that they comply with BS EN 61439-3, which most everyone seems to forget.

So if your DP 100A isolator or switchfuse does not comply with BS EN 61439-3, you cannot install it irrespective of whether the enclosure is metal or even if you enclose it within a metal cabinate or enclosure.

Unfortunately, BS EN 61439-3 only applies to CUs, so you won’t be able to install either a DP 100A isolator or switchfuse.

 

[Deleted member 26818]

Should point out, that the previous post only applies if you believe DP 100A isolators and switchfuses are similar to CUs.
If you don’t believe they are similar, then you can still install them and they can be plastic, metal or whatever.

 

[Midwest]

Should point out, that the previous post only applies if you believe DP 100A isolators and switchfuses are similar to CUs.
If you don’t believe they are similar, then you can still install them and they can be plastic, metal or whatever.

I believe I'm paying too much tax to HRMC. I'm arguing, they are not believing.