New CU and meter tails etc

[rajshar]

In response to buzzlightyear. Thanks for your reply.
I don't know if he is going to do EICR before doing any work but as I remember our conversation, EICR was never mentioned. He did say EIC after the installation and test. Again I don't know which test/tests will be done.

My next door neighbor is a builder working for the council and renovating the council properties from scratch. This electrician is his friend and also does the work for him. I don't know if he is independent or working for a firm. I'll surely ask more questions. I have seen his work next door and that seems fine to the naked eye.
Thanks

 

[rajshar]

Thanks Strima, telectrix and westward10.
I thought the earth cable from cutout with the tag "Do not remove" is the main earth and it is going in to the fuse board, routed behind the ply board. My understanding is that my electrician should upgrade the tails to 25mm from the meter to CU, regardless what is from the cut out. He should also be able to upgrade the earth bonding from the CU to gas/water pipe provided I still need it as the street pipes are plastic.

What can I ask the suppliers electrician other than his usual work of fitting an isolator. Obviously he is going to take the fuse out for a safe work environment. If I supply him the tails and earth cable, can he change them. Obviously a lot will depend on his mood and schedule.
Here is the pic as requested.

 

[rajshar]

Just realised that If an isolator is fitted then my electrician can't change the tails from the meter, he can only change from the isolator. So now definitely I will have to ask the supplier's electrician,vif he can upgrade the cables. I will get the cables anyway, whether he does or not.

 

[rajshar]

Thanks Mike Johnson. That earth cable from cutout is going in to the fuse board and then another one of same size comes out up to the gas pipe. From this joint of gas pipe it just goes underground to the kitchen, possibly to the water pipe.

 

[Strima]

The installer who fits the isolator should fit the correct size tails, but they may only do this from the meter.

This diagram shows you who is responsible for each bit, it's taken from a DNO guide:

 

[rajshar]

Thanks Strima.
The suppliers installer will fit the correct cables if he deemed necessary. between meter and isolator and between cutout and meter as anything after cutout to meter is the suppliers responsibility.

Now I could be completely wrong but isn't that with a 100 amp fuse the 16mm tails aren't suitable as they have maximum rating of 80amp. We had smart meter fitted April 2020. I am just wandering that why they didn't upgrade the right tails or downgrade the cut out fuse that time. That time I knew nothing about any standards or regulation otherwise I would have asked the installer for this and would have arranged for an isolator at the same time.
The other issue is the earth cable. Now we don't have the earth conductor or earth block. The earth cable goes direct to the fuse board from cut out. The current earth cable doesn't comply even with 16mm tails. I believe it should be 10mm in the current settings and if upgrading to 25mm cable it should be 16mm. Even this wasn't pointed out to us by the meter installer. May be it's not their job to change the cables but at least during the installation, they should be inspecting that equipment is in compliance. Or is it that my equipment is still in compliance because new regs don't apply retrospectively. Anyway when suppliers installer comes to fit isolator and decides that 16mn tails are good enough, shouldn't then who ever is responsible, change the cut out fuse to the correct rating. Although upgrading the tails should be the best option.

Now some electricians have no problem to upgrade the earth cable and some just getting out of it by saying they don't touch the cutout as this 2nd electrician said. It also makes me wonder that how he was going to change the CU without any isolation because he didn't knew that I had arranged for an isolator to be fitted. I think I should at least ask one more quote and see what he/she can or can't do.

All this brings up new questions. All the CUs come with 100 amp isolators. Do we still need an isolator inside the CU, if one fitted outside, if yes should it be lower rating than the 100amp?

Thanks.

 

[brianmoooore]

100A is the max. rating of the cutout fuse holder. 100A fuses were common several years ago, but the DNOs have been changing them to 80A when the opportunity arises on 'normal' supplies.

 

[rajshar]

Earlier telextrix said that BG CUs are good. Sorry I didn't meant that BG boards are bad. It's that he was going to get the BG CU from Screwfix and all the prepopulated BG CUs with RCBOs they sell come with Type AC RCBOs. I want Type A RCBOs and I was thinking to get the wylex ones from TLC. Anyway now I found that TLC does sell BG brand Type A RCBOs as well and it comes around £107 pound cheaper than Wylex, it's not that big difference.. Now it's just a struggle to chose between Wylex and BG.
Thanks

 

[rajshar]

Thanks brianmooore. So do you think that when smart meter was fitted, they would have changed the fuse. Do they not put any notes etc about the rating of the fuse as I don't see anything to indicate. Do you think that someone should have pointed out that earth cable needs changing.
Thanks

 

[Vortigern]

It is not necessarily the case the earth cable needs changing. The braided earth is supplied from the DNO and it is their equipment. The energy supplier (in theory) should not touch the DNO equipment and vice versa. It depends on the fault current likely to occur at the CU. Personally I would not fit BG my experience with them has been they are unreliable and I have had quite a few failures with their RCBO. The earth cable from the DNO supplied earth to the CU can be changed no problem but then there must be a reason to do so such as thermal damage for instance. Why are you changing the CU anyway?