16mm tails with 100amp fuse?

[nikinoo70]

I am going to be changing the consumer unit in a house. The owner arranged to have an isolator switch fitted by N power (free of charge). Ive been to look at it and the guy has fitted it with 16mm tails. The customer was told that this was because the tails to the ccu are 16mm. But it has a 100amp fuse. I will be fitting a new 9.5kw shower and the cooker is electric as well as the usual ring main and lights ect. It is a 3 bed house. I was going to change the tails to the ccu to 25mm.

Am I correct in thinking that he should have fitted 25mm to the isolator switch? All the tables ive looked at say I am.

 

[Geoffsd]

Is that not using 50% more copper than necessary?

 

[Rauer]

Just pull the carrier and have a look

 

[JD Hogg]

Has anyone ever asked the DNO to downgrade the main fuse from 100A to 60A or 80A? If so did they do it?

 

[Rauer]

The DNO fuse as far as I am aware is to protect THEIR tails to the meter not OUR tails from the meter!

 

[i=p/u]

maybe but i would of thought fuse at their green box, so was for consummer, byt this is a good guess

 

[Taylortwocities]

Just pull the carrier and have a look

Well, that just does away with the whole point of having the isolator fitted in the first place!
To pull the fuse, you'll have to break those new seals that the DNO just fitted

In any case, it may not tell you much - many of the fuse carriers have the fuse cartridge riveted in so you just cannot see the fuse rating.

Per the above, your responsibility is from the isolator. If the DNO's fuse pops then its their problemo!

 

[i=p/u]

thats what i was thinking, you cant see the fuse

 

[Rauer]

Well, that just does away with the whole point of having the isolator fitted in the first place!
To pull the fuse, you'll have to break those new seals that the DNO just fitted

In any case, it may not tell you much - many of the fuse carriers have the fuse cartridge riveted in so you just cannot see the fuse rating.

Per the above, your responsibility is from the isolator. If the DNO's fuse pops then its their problemo!

What are these seals I keep hearing people talk about?

I have never to this date seen a fuse carrier that has been riveted in!


If you want to fuse down the main tails then install a kmf ....... Problem solved!