Questions on new CU, Tails and Earthing.

[Andy_S]

Hi, new to the forum but have found it to be a great source of info in the past. I am qualified to 16th edition but as i'm a maintenance engineer and mainly work on machinery rather than domestic installations i'd like to ask the following questions to make sure i get it right!

I'm looking to replace my consumer unit, a 60A Wylex rewireable with minitrip bases fitted, fed by what appear to be 16mm tails.

I have asked the DNO to fit a double pole isolator so i can work on a de-energised system, If i feed my new CU with 25mm 6181Y will the DNO have to upgrade the cable from the cutout to the meter and from the meter to the isolator. If so, is this additional work chargeable or will i get a freebie as i'll be paying (through the nose ) for an isolator. I have a Western Power Distribution / N-Power combo, TNC-S supply.

I'll also be replacing my main earth with 16mm, and the bond to the gas and water pipes too. Will it be ok to clip the 10mm earth direct to the exterior of the house to go from front to back with out mechanical protection, i have a half rendered house and the cable will be hidden nicely by clipping up under the bellcast stop beading?

I will be having a PIR done to make sure all is ok but want to get most of the donkey work out of the way.

Thanks in anticipation!

 

[Deleted member 26818]

Why are you intending to install 25mm² conductors?
If it's only a 60A supply, 10mm² will most likely be sufficient.
It's unlikely that the DNO will replace conductors for free, unless they're damaged or show sings of overheating.
As for upgrading them, why would they need to do so?

 

[SPARTYKUS]

Future expansion :38:

 

[Andy_S]

Will Clarify, existing CU that i want to replace is 60A rated fed by 16mm tails. Want to fit 100A rated CU which will require 25 mm tails. Think the DNO's cut out is 100A, though.

 

[telectrix]

the cut out may say 100A on the outside, but it's anybody's guess what's inside the black magic box.

 

[Andy_S]

Bit of a result, Npower's metering agent will fit a DP isolator between the meter and the CU free of charge. DNO don't seem concerned about conductor size either side of the cut-out, especially as i'm not increasing load .

 

[telectrix]

if it's a meter fitter fitting the isolator. i'd be certain to check the polarity of the tails after.!!!!!