Hi, does this help. 

It certainly confirms what I told him - that the tails and the RCD were all his responsibility, even if he isn't authorised to touch them.

I suspect it's down to poor workmanship by the meter installer's contractor, which may have been replicated across a large number of properties if a similar approach of allegedly installing tails under tension was followed.

What I couldn't quite understand was that as a result of the fault, and there not being a local earth after the removal of the incoming earth from the pole transformer, tests showed that live and neutral were "inverted", such that metal objects such as the shower and Aga became live, his heating pump failed and the solar inverters also showed as failed (although once the system was repaired, they all recovered OK, but not before he's had to pay for some investigation)

if the consumer is not permitted access to inspect everything?

I'm not sure that's quite the case. There's nothing (legally) stopping an owner picking up a screwdriver and opening up the enclosures. Even if sensibly it would be recommended that if the owner didn't possess suitable electrical skills, that the actual doing of it should delegated to to someone who does. DNO/supplier stuff would normally be sealed to (legally) prevent access by anyone else, but consumer owned equipment shouldn't be.

On the other hand, if the problem was caused by the supplier's meter change causing the cables to be moved (or re-terminated) - so causing a loose connection in the consumer's equipment, I would have thought that the supplier would have failed in their general duty of care. This after all is a well known problem in the industry - some consumer unit manufacturers now include extra cable clamps to mitigate that very risk, so it would be reasonable for the supplier to take precautions to mitigate the risk - e.g. checking the tightness of consumer side terminals or even formally informing the domestic customer of the risk and recommending they engage an electrician to check the installation (like they sometimes do when they spot inadequate earthing).

The problem of course would be proving that the meter swap was the root cause of problem and it wasn't the result of something else - e.g. a latent fault in the RCD itself, causing overheating, which then loosened the terminal; or even later tampering (by person or persons unknown). That's the sort of thing lawyers make their money out of.

live and neutral were "inverted"

That's a common enough condition. It can be seen even when the supply earth is perfectly good, if one of the lines gets connected to true Earth. The typical cause is a L-PE fault in a TT installation with a faulty RCD. In effect both LV conductors are connected to Earth (rather than just the N) so the potential to true Earth is then a tug of war between them with N (and hence supply PE) ending up being a long way from true Earth, with large step voltages around the both means of earthing.

   - Andy.

Andy

Thanks for that.

I do think that this long after the meter was replaced, it's going to be challenging to prove that the installation was at fault.

I've suggested to the guy to gather as much evidence and information that he possibly can, along with the reviews from his electrcian and responses from the ministry (he never aims particularly low!) and presents the case as best he can, otherwise it's all down to him, and most organisations now seem to take the view that the buyer or consumer is the ultimate responsible party unless proven otherwise!

Peter

Ideally these days the supplier will provide an isolator after the meter - then the demarcation is simple.

The tails leaving the meter are your suppliers and everything before the meter is your DNOs.

If you can see missing insulation then telephone your supplier. If your supplier is being awkward then mention the ESQCR regulations because ultimately its their equipment and they are obliged to maintain it in a safe condition.

In my experience once you tell them that uninsulated conductors are on show then you can expect the MOP to be visiting typically within 24 hours. So no point trying to DIY this or even paying an electrician to. The supplier is responsible, let them do it.

What was wrong with the old meter tails? Too short?

I think that they belong to the consumer. When I had a new supply installed, the "consumer's tails" (see OSG Chapter 2) were connected to my isolator, which made life easy for the supplier's installer.

Be that as it may, as Andy has pointed out, whoever touched them last is responsible for the state of the connection by virtue of owing a duty of care. I also agree that it may be difficult to establish negligence - that is where experts (like JP) come in.

I think the old tails were the wrong colours, so the meter installer replaced them, Anecdotally, it sounds like instead of leaving an s-bend to spring them into the RCD, they ended up much shorter.If the terminals were torqued correctly, it shouldn't have caused much of an issue, but since the device was an existing consumer one, they possibly made an assumption, or forgot.

ESQCR is a good call because of the overhead power supply and some changes to the pole-mounted transformer earlier (this year, I think). It was suggested that the earthing system may have been changed at that point from TNC-S to TT. I haven't got any evidence myself, but if there was no good local earth, then that could throw a wobbler to the safety at the property!

That would explain why the installation is fronted by an RCD - if the DNO decided they can't provide an earthing conductor.

As I say, just get the supplier out. Worse thing that can happen is they take a look and say its not their's. But if there's no isolator then technically the MOP should be the one changing the tails to the meter anyway - even though most electicians will cut the seals and do it.

Most suppliers will install an isolator for typically < £100 anyway. Then you know exactly where the demarcation is and your electician can work safely without needing to depend on cutting seals or waiting for DNO/MOP.

Stuff beyond the output side of the meter is not normally DNO sealed.
It may be customer sealed (landlord's supplies to prevent tenant theft are an example or just as an anti- tamper precaution in buildings with  unknown users - our Scout hall does this for example - anyone can open the cabinet door to reset a breaker, but to open the box requires  seal to be cut.)
The customer is at liberty to cut (and replace or not) seals on Henley blocks switches  so on that are downstream of the meter - and this is often done where there is a split to more than one CU for example.

Mike.