Radian

Excellent; Which is why I discounted that approach but a highly sensitive CT would be just the ticket. Could be fun to plot!

You're going to have to get up close enough to touch it to be certain. If it's lead (which it doesn't look like to me) then you'll be easily able to gouge it and see a bright mark appear. If it's zinc a magnet will stick, otherwise it's aluminium. I think it's zinc.

About the same as a 55" OLED then, but without the action scenes.

Yes, you're absolutely right. The SMPS in the USB sockets shouldn't really present any resistance breakdown even at 500V. I think I may have found the problem though. One thing that seemed odd was the coincidence between an MCB trip one day and two apparently random RCCB trips subsequent to that and I think I now understand the link. When I unplugged all the equipment in the workshop I had in fact left a 6-way extension lead in one outlet. Just now I was removing and testing each USB equipped outlet in turn when I found the one hosting the empty 6-way extension was the leaky one... It wasn't the USB outlet, it was the empty 6-way block! That was a surprise, and the reason soon became clear on opening it up... It was an old 'surge protection' block. With a very helpful pair of MOV's between L->E and N->E and a third between L->N MOV's degrade when they absorb voltage spikes so the apparent coincidence with the MCB tripping could be explained by them becoming leakier after taking a back EMF hit the day before. There is one slight oddity in that when the RCCB tripped first thing this morning, the 6-way extension was isolated from Live via a smart socket that was switched off at the time. But N would still have been connected and the MOV between N->E and could still present a current imbalance that might trip the RCCB. Hmm, that would be an interesting thing to log for sure - but how? Obviously the equivalent of a pair of antiphase CTs like in a regular RCCB would be what's needed but achieving this in practice sounds more than a little tricky. It's an old plastic fantastic single RCCB breaker unit:

Last night I flipped all the MCBs off before resetting the RCCB in an attempt to see which circuit might have an earth leakage fault. I put most circuits back on one at a time but it didn't trip. However I didn't switch back on a 16A radial circuit in my workshop that has five double 13A outlets. When I switched that on today the RCCB tripped immediately. Simple? Not quite... The five outlets had nothing plugged in, so you'd expect an insulation breakdown somewhere in the wiring. My insulation resistance tester at 500VDC reports 1.2 megaohms (both L->E & N->E) which would be suspicious for plain old wiring and sockets but these are all USB equipped outlets, so some leakage might be expected. 1.2m equates to 200uA which is a long way off the 30mA that's supposed to trip the RCCB. Each individual outlet could just be leaking 40uA so not an earth shattering amount. I see two possibilities here, the 200uA just pushed it over the trip point by adding to a substantial existing leakage elsewhere and/or the RCCB is faulty and tripping on too little current. A very sensible check but if any of LNE became high resistance why would this create a residual current fault?

That was a full-on afternoon getting the new fridge fitted! Because it's in an integrated housing the door had to be swapped over and of course all the holes were in different places. The old hinges fitted in standard big round cutouts like regular kitchen cupboards. The Liebherr has totally different style so I had to hole saw out some plugs and glue them in to fill the big old holes. Then getting the 72kg fridge in the niche was huge fun. Not least because the mains lead was too short to reach up to the socket on the wall above the kitchen units. Anyway, all in and running now. Only within 10 minutes of firing it up for the first time the RCCB tripped in my CU. Don't think the fridge is to blame as resetting the trip, everything is back on and has been for a couple of hours. Bit of a mystery that.

I thought MCB's were pretty dumb so wouldn't expect them to trip without due cause. RCCB's are a tiny bit more sophisticated so I would be less surprised to have one trip out for no good reason. The thing is, last night at around 8PM the MCB for the kitchen end of the house tripped and on investigation the 2.5kW heater in the dishwasher had just come on for 2 minutes prior to the MCB tripping. Very suspicious and I was bemoaning the fact that we'd literally just bought a replacement fridge, installed today, and that all our appliances were bought at the same time (24 years ago) when we built the house - so they were all failing at the same time! However, tonight at 8:27 there was another outage only this time it was the RCCB common to all ring finals that went. This gives no clue as to what caused it as resetting it made everything come back on and stay on. The only suspicious thing is that precisely 8:27PM was Amazon's idea of sunset and a routine was in operation that would turn on a bunch of smart bulbs. A huge coincidence, except it doesn't really fly as a theory because all those bulbs were already permanently connected to the AC. Only the LED's would be turned on and they're so far removed from the simple kind of switch that could suddenly connect Live (or Neutral) to earth as to be extremely unlikely as a cause. Plus the earth connection is very remote from the bulbs, not physically connected to anything. So I'm struggling to diagnose the problem, and started wondering if it was possible that the MCB's and RCCB in my CU are yet another '24 yo. appliance' at or near EOL?

As I said above, it looks to me like the felt might have come away and is laying crumpled up against the sloped roof. A good strong gale might have done it.

Liebherr due to be delivered tomorrow! 😃 ...But you couldn't script it: Having successfully nursed the old Neff with my own control system to keep the goodies cool since last week, tonight I get a notification that I put in place to advise me when the temperature has exceeded 7oC A quick investigation showed the 32A MCB for the kitchen ring had tripped. First thought was that the Neff compressor was finally toast. But my power logger showed it was off at the time. What was odd (to me at first) was 2 minutes of 2.5kW above base load, just before the trip event. Son then joins in with the sleuthing and points out that he had put the dishwasher on earlier. 😬 So now we need a new dishwasher 😵 Of course all the kitchen appliances were bought new when we built the house 24 years ago. How they make them have such an identical lifespan is impressive. Two freezers to go next week then.

12kWh includes your self generated energy or just your import?

So, something close to a linear interpolation between the 'official' lower thermostat pocket and the hot takeoff at the top should do the trick. Easy to clamp a probe to the pipe union up there. Natural stratification would keep the hottest water at the top regardless of the location of the indirect heat source. I'm not sure if there's an active circulating system to de-strat the tank or not. The brand name hints at something like that but it could be nothing. In addition to all the marketing BS, a 75W standing heat loss would put me off that product. If all you want to do is have a graphical display of temperature and heat 'charge' and additionally get voice control of setpoint/boost etc. all that needs is a couple of 1-wire sensors, Raspberry Pi or similar and a bit of software.

Got the Mixergy manual downloaded. Digesting it now.

What's the extra monitoring on the mixergy then? All I could see is the rather easy to replicate, but ultimately pointless, cloud control.

Architects have an array of cop out clauses they like to employ. "To be designed by others" is the one that makes me giggle the most. I've got a similar story to the OP but haven't got the emotional energy to write it up. The upshot was an unexpected change of plan and spend of several K. We really shouldn't have let them off the hook (another case of incorrect measurement) but we did. The real kicker was when we got a substantial bill over one year later for a site visit that our builder had arranged with the architect to try and solve the problem (which it didn't). The Truss manufacturer solved it in the end. They were golden.

That should be OK but be warned that turning down the boiler flow temp might end up with it not being able to meet the demand and staying on unnecessarily. We're a family of three spread over 280m2 using around 15kWh of leccy a day, and the same again for gas. That's a condensing system boiler with flow temp set to 63oC and a vented HW tank set to 55.0oC And I mean 55.0 as I chucked the old analogue thermostat and use a digital sensor connected to the Raspberry Pi that does all the heating control. Like you say, the dial types are just too imprecise.

CE = China Export, sometimes.

Would that be the back bedroom with a dormer? It looks like dormers to front and rear and the latter seems to have lost its felt completely.

Why not apply a square law to the kWh charged. That would give some real redistribution.

Very true. Is your 10mm glass the norm now? I had fully glazed internal doors in a house built in 1987 and they were around 6mm from memory.

Google "Faux Crittall" for some more ideas. You can glue dividing strips onto glazing panels for simplicity. I expect you would really like to know how wide to make the timber components for strength. Take a look at the skiniest off-the-shelf doors and window frames for the absolute maximum required. Can you perhaps adapt something in the way of off-the-shelf doors?

Yes, would have saved me hours of fun but the run goes under a couple of walls and under a road. It all gets a bit 3D above ground! It's also 75m to the discharge point into a stream but there's an inspection chamber about half way along. Fortunately it was blocked just over 2 rod kits away so managed to borrow the last couple of rods from next door. Interesting topic to me, as I have another run where the builders used a Y piece to turn a corner and just provided a rodding eye off one branch instead of an inspection cover. Is that permitted? Makes it hard to guess where the run is from above ground.

I pictured them burying a pickup truck for that.

Oh yeah, well, they should change those for something more tasteful immediately 😁 First person to say 'Dentists' gets blocked 🤣

When we were looking for the position of a blockage in an underground storm water pipe I made a gadget that created a really big 1mHz magnetic field and a tuned receiver with an LED crossbar display. It could pinpoint the end of the drain rod we taped it to to within about 75mm when the vertical separation was around 0.75m. The error through a wall at half that depth would surely be small enough for this kind of thing. I must dig it out and test it properly. I did originally try it out through walls inside the house including one that had a steel radiator on one side. Against my intuition it still worked in this situation although I didn't pay attention to accuracy.

I'm going to respectfully disagree 😂 It may be vertical blinds that are shunted fully to one side of the track to show-off the bedroom for the photo. If so, they probably spend most if not all of their time pulled across but tilted to control light and privacy. Under these conditions an uninterrupted view (from a favoured angle) is available that wouldn't be with a narrower window opening. At least that's my feelings. The only thing that looks a little weak to me is the rectangular window at the first floor level. It cries out for a bolder statement here. Maybe a bigger diamond shape matching the roofline?