Distribution Board Not compliant with 17th edition

[Dave1982]

ZS at consumer unit read 0.2 ohm

 

[Roger]

"Cable feeding flat from switched fuse 100A from photo looks like 10mm line and neutral, earth nowhere near 16mm"

Is that right,unless i am missing something putting a 100 amp fuse on 10mm cable is a bit dangerous or have I lost something in translation.

If so shouldn't that have a 40 amp fuse to protect the cable.The flat won't use more than that,or will it ? is it large ?
Zs would be better if you were to use a lower rating of fuse.Any chance of getting a Ze ?
I upgraded all over 10 and 16mm to comply,16 meter run on 10mm and it made .01 difference on my Zs.
But it had to be done,with so little circuits I would use RCBO's throughout as the price seems to be getting better and better these days.

 

[oldtimer]

Dave first of all check the size of the fusewire back at the MEM switch fuse I assisted a guy who took it for granted that there was a bit of 60 amp fuse wire fitted until I prodded hime to take it out and found a bit of 2.5mm copper accross it. Might be an idea to change it to a cartridge fuse and carrier me thinks you can buy these or if there is an isolator secton fitted there nothing stopping you fitting a circuit breaker within the enclosure.

As for your delima well Malcolm me thinks you are spot on and depending on the age of the building you may find that it was designed originally with small power and a couple of light circuits and since then the extras have been the cooker and the shower circuits and yep I agree you are not upgrading the board to take another wing on infact you are picking up the same circuits and making it safer so my view would be the mains can look after themselves at a later date. I was called out a couple of weeks ago where the tenant thought "any fool can change a shower pull cord switch" so when it went bang he actually (I thought) tripped the main fuse so I sorted his pullswitch and he called out the DNO who found it was not the main service fuse that had blown but the one in the cupboard at the bottom of the stair.

One thing that niggles me here I remember asking about a situation years ago where the supply cable to the flat was not big enough ie 10mm istead of 16mm but I was told that due to the short cable run then 10mm was ok as it could take the load. Mind in my house I have a imperial version of 10mm micc supplying my board.