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Discussion Starter #1
Hi folks,

I'm pretty clueless on electrical matters and have seen some pretty knowledgeable posters on here, so I hope y'all don't mind me posting what are probably some quite silly questions.

I'm getting ready for installation of a home charging point. I want to get my main fuse upgraded to 100A, and the DNO have said "first make sure you've got 25mm tails from fuse to meter and meter to consumer unit".

I understand that fuse-to-meter is my electricity supplier's responsibility, and meter-to-consumer-unit I need to get an electrician to handle. However, one thing that confuses me is how an electrician is supposed to isolate the supply in order to do that, since I understand that pulling the main fuse is a big no-no. Does that mean I should be trying to get my electricity supplier to do that as well at the same time as they handle their bit?

I know it's desirable to have an isolator switch so that this stops being a problem - and I actually do, but presumably that doesn't help if the tails to that need upgrading too...?

Also, the current one is only rated for 63A. But it looks to my untrained eye like the actual switches are removable. Do I need to get the whole thing replaced, or just the switches? And if the latter, is that something I can do myself, or is that a sparky job too?

Photo of the current setup below in case it helps. (The tails from the main fuse look slightly thicker than the others to my eye - maybe they're already 25mm? The meter was replaced with a smart meter recently, I've heard suppliers sometimes upgrade the tails at the same time as doing that...)

Thanks in advance!

IMG_20200604_193455.jpg
 

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Sure there'll be lots of people along sorrtly to give you the detailed answer...but the short version is the whole thing is a job for an electrician. The task will be protected by pulling the main fuse, allowing the tails from fuse to meter and meter to consumer unit to be replaced, assuming this is required, and the switch to be upgraded. The main fuse itself can also be checked and upgraded if required.

The important bit...you can see that the main fuse is protected by a soldered seal. An authorised DNO rep needs to attend to remove the fuse and break and remake the seal. It is illegal for anyone else to do it. If your electrician does it and subsequently it's detected during a meter reading then you will have to explain it.

So you need to get two or three quotations from reliable electricians, and make sure they're going to do the job the right way. Hope this helps.
 

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Have a close look at the blue & brown wires from main fuse to meter, the size in mm should printed on them. I can see some printing on the blue.
All four wires connected to your meter seem to be the same size, so if the blue says 25mm then you're good to go.
If it says under 25mm, then call the electric company to swap them.
 

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Another option if you have some callipers, 25mm meter tails are 11mm outside diameter...

Some DNOs are fine with electricians pulling the main fuse - they just need a phone call afterwards. SSE for example work like this.
 

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Also, the current one is only rated for 63A. But it looks to my untrained eye like the actual switches are removable. Do I need to get the whole thing replaced, or just the switches?
They can be replaced individually but it is a job for a Sparky. However, you may not need a larger one as it is probable that the Charge Point wiring will bypass your existing consumer unit and have its own mini unit and switch. How easy is it going to be to run a 6mm^2 cable to the outside? Also, how far away is your charge point going to be?
 

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You need what is known as an authorised electrician who carries a small set of seals to reseal the main fuse. The electrician has to account for the numbered seals and notify the DNO for permission to pull the fuse in the first place and make good. The authorised electrician will do this over the phone while on site and later do paper accounting for the seal he has used.
 

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Even electricians who are authorised to pull the main fuse (DNO property) are not allowed to break the seals on the meter (electricity supplier/biller property). So he can't change the tails into the meter even though he can kill the power through it.
 

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If the existing panel is full, Chargemaster will ask for £50 to supply & fit a mini consumer unit as part of the installation.
 

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There is a lot of weird stuff above....

You already have an isolator switch between your meter and consumer unit (CU) so that makes life a lot easier. Best option is to send that photo, plus some close up ones to a few charging companies to get quotes. It is possible the (large) CU may have space to accommodate the components or you may need a separate one for the charging point, but they will be able to advise.
 

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Discussion Starter #12
Thanks everyone!

Some installers I'd guess would just split the feed coming out from the isolation switch and fit a mini consumer unit just for the charge point.
That's exactly what I'm expecting to happen - the main consumer unit is full, so I'm expecting Henley blocks and a mini consumer unit after the isolator. I'm considering Pod Point, and they include that in the standard install. But that's why I'm concerned about the isolator only being a 63A one.

Have a close look at the blue & brown wires from main fuse to meter, the size in mm should printed on them. I can see some printing on the blue.
All four wires connected to your meter seem to be the same size, so if the blue says 25mm then you're good to go.
If it says under 25mm, then call the electric company to swap them.
Good call! Although the printing you can see in the photo turned out to be irrelevant, a closer inspection revealed some very faint lettering that did indeed include "25mm^2", both on the fuse-to-meter tails and isolator-to-consumer-unit. Sadly, although it might look in the photo like the meter-to-isolator wiring is the same size, it's not. There's no writing on that set, and sadly I'm lacking in calipers, but trying to estimate with a measuring tape, I'd say it's 9mm diameter vs 11mm for the others. That fits with the 63A isolator, so it looks like I'm not getting off scot free.

<shrug shoulders> "Dunno mate - could've been like that for years for all I know."
I have a smart meter, and I've read stories of someone from the DNO turning up while the electrician is still on-site to find out why the smart meter is reporting power loss...
 
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