New consumer unit (not DIY)

[Theo]

Several issues. One is lack of RCDs could find undetected cross-wiring - eg lighting circuit borrowing neutral from nearby sockets. Or just straight leaky appliances - an old boiler, immersion or something.

The other is the general condition of the installation: if the CUs are that old, how old is the wiring? Do you know it's sound - not rubber, not cotton, no 'green goo' (failed PVC insulation)? Earthing in place where it's needed?

For something of that age you might be advised to commission an EICR (£100-200) and get the system tested. Testing is part of the CU change anyway, so it's work that needs to be done (although an electrician should retest once the CU is replaced).

Having done an EICR it's essentially a todo list of work that needs to be done, and you can then show it to people when you're asked for quotes. It puts them on more solid ground than quoting for a CU change, taking it apart and discovering wiring issues that make the job much bigger. It may result in lower quotes if it means they need allow for less contingency since the job has lower risks. It may also allow you to fix more things on the EICR while the electrician is on site.

Theo

[Roland Perry]

In message <t09sor$kvg$ [e-mail], at 09:41:47 on Wed, 9 Mar 2022, David Wade [e-mail] remarked:

Like I said, I'll look that up later.

[Roland Perry]

In message <2ii* [e-mail]>, at 09:54:06 on Wed,

9 Mar 2022, Theo <theom+ [e-mail]> remarked:

Seems unlikely, there aren't any sockets (which are all at floor level, rewired under the floorboards) anywhere near the lighting.

No immersion. Boiler isn't particularly old.

Looks relatively recent, the house had a big refurb about 20yrs ago and I expect it dates from then. (Unfortunate they didn't do the fuse boxes though, but did decommission the old round-pin sockets).

So perhaps if the electrician can first do an up to date EICR then come back later to quote for the remedial work? He's very local.

[John Rumm]

There is some argument for switching existing stuff to a new CU if it means you get RCD protection on socket circuits that currently have none, or if you have re-wireable fuses and the place is likely to be occupied by people not able to re-wire a fuse etc.

[Andy Burns]

Confine him to that then

Most of which isn't yours to upgrade, no isolator after the meter?

I understand their attitude, the more things you do at once, the chances of finding some undocumented interaction between them rapidly increases, and the one person who knew about the baler-twine holding it together left years ago, you get more departments involved, they all want you to sneak their own pet change in at the same time ...

[Theo]

It seems like that's already been done: the geriatric CU remains, a secondary CU has been added for the extension. At some point the installation is unsafe and somebody has to bite the bullet and be prepared to rectify anything that may be lurking. While a 'sleeping dogs' approach might be fine if the installation is actually OK, just not up to current regs, from the description I'm not convinced this installation is OK.

Theo

[John Rumm]

Much will depend on the actual fault, and the general state of the wiring.

You can usually find that much quicker with access to both ends at the circuit at the CU - you don't even need to take a socket off:

If you get a continuity failure at the ends, short one set together, and then use a ohm meter connected to a test plug. It will quickly show you which sockets are either side of the break.

[John Rumm]

There might be - but in general it is better to find and fix them than ignore them... that would count as upgrading to a more modern installation as well IMHO :-)

[Theo]

'Looks' doesn't just mean the colour of the sockets, but what's going on with the buried wiring. If they're replaced a round pin socket with a new faceplate but connected it to rubber wiring, I'd be worried. PVC could look OK from the outside but be corroding inside, etc.

For something of that age an EICR is an extremely good idea to check if there is anything lurking. Maybe they installed completely new modern wiring runs and capped off the old ones, but maybe there were some bits where they didn't do that. That they didn't also change the CU at the same time suggests it wasn't an entirely new installation.

Sounds like a plan. A good EICR will take a few hours minimum. But worth it for knowing that you're living in a house that doesn't have any electrical timebombs.

On the CU question, given the 'interesting' history I might be tempted to merge the old and new CUs into a single new one. May cost a bit more, but will remove the past heritage of additions and bodges, leaving you with a single modern electrical system. If you go for an SPD as well, that will surge protect all the ways, and can tidy up some of the meter box wiring (no Henley blocks to tee off to the second CU, maybe make space for an EV charger).

WRT meter tails, ask your electricity supplier how much it would cost to upgrade them. They own the meter so tails either side of the meter are their responsibility. There's a bit of variation between suppliers as to how much it costs.

Theo

[Robin]

On 09/03/2022 10:43, Theo wrote: <snip>

the tails from the meter to the CU are the customer's as part of the internal wiring

[Andy Burns]

Most sparks seem willing to cut the seal(s); when I replaced my CU (before part P) I cut the fuse seal, inserted the 16mm tails out of the meter into my own cut-out, then used 25mm tails into my new CU, also upgraded the 6mm earth to 16mm.

A few years later when the elec meter was being replaced, the fitter noticed the new tails on my side, and replaced the tails from cutout to meter and meter to my isolator with 25mm, he replaced the 60A fuse with an 80A, re-sealed the cutout and sealed the isolator input side.

So I didn't have to pay anything other than for the isolator.

[Andy Burns]

isolator

[Roland Perry]

In message <0ii* [e-mail]>, at 10:43:04 on Wed,

9 Mar 2022, Theo <theom+ [e-mail]> remarked:

I was commenting on the wiring emerging from the old fuse boxes.

It's all been added later.

The obsolete round pin sockets are incompletely different places to the new 13Aones.

The wiring appears to be.

The fuse box area is so far from wherever I might park a car, that's a non-starter.

I already did. They said "whatever to person you need to hire to do that, charges you".

Not according to the UK Power Networks (nee Eastern Electrickery) people who came round to do a free survey.

[Roland Perry]

In message [e-mail]>, at 10:11:07 on Wed, 9 Mar

2022, Andy Burns [e-mail] remarked:

The tails from the meter go into three different (one newish, one medium, one ancient) fuse boxes, each with their own ON/OFF switches. There's not one master "all three off" switch between the meter and the fuse boxes.

This is three separate changes to a really simple Access Database. A teenager ought to be able to do it.

[Roland Perry]

The kitchen/extension sockets on the newest box already have that.

The biggest problem post-Brexit post-Covid is finding anyone with the fuse wire in stock.

[Roland Perry]

In message <2ii*R+ [e-mail]>, at 10:17:18 on Wed,

9 Mar 2022, Theo <theom+ [e-mail]> remarked:

Tertiary.

The geriatric and secondary units definitely need replacing. That's all.

[Andrew]

Big firms have big overheads that means they are always more expensive. Far too many one-man bands resort to lies and bullshit, especially when dealing with older people.

[Andrew]

But the meter is sealed so the 'customer' cannot access them, so ought really be down to the electricity co to change them.

[Andrew]

They only moonlight if they are someone else's payroll. If they are self-employed then they can work whatever hours they choose.

[Andrew]

When I bought my current (1976) house in 1991 I noticed that the metal cover above the wylex rewireable fuses had scorch marks above both the cooker and ring main 30amp fuses.

Many years later I needed to remove the wall cabinet above the cooker main switch (kitchen was refitted by previous owner) and discovered the 6mm cable had been exposed and was surrounded by a huge burn mark, and where the numpty had drilled through the live *and* earth, it had been 'repaired' with a bit of choc-bloc !!.

Another few years later I removed another kitchen cabinet above a wall socket and found one of those hammer-in picture hooks right through the ring main cable neutral. Still don't know how they blew the 30 amp fuse but the cooker one had melted a small quadrant out of the metal shield above the fuses.

I had a full survey that never mentioned it or some really bad faults with the baxi back boiler either :-(

The lighting circuits in the loft all had 'green goo' coming out of the insulation into the loop-in fixings so I replaced all that and fixed the borrowed neutral on the hall/landing lights too.