-rick-

Even if on good terms I think I would still want something in writing from them.

So far the neighbours builder is. Not sure we have established whether the neighbour is. Maybe the neighbour just doesn't know better and the builder has promised to deal with everything. Still it's not a good start so be careful but still might be worth talking to the neighbour to try and keep everything on good terms (worth calling insurance lawyers first though I'd guess).

Also, just thinking about the situation you'd be in if the voltage was 207V. It would mean that the local substation is under very heavy load from a local consumer and near tripping off. Therefore, the extra current produced by your inverter at that voltage might be the thing that prevents the grid from tripping. An argument may be that the current limit protects the cables, but I would guess that it's the substation transformer that is the limiting factor in almost all locations. In fact the areas where you may see voltage dipping to near 207 are likely all rural with pole transformers and long lines. Likely meaning that a generator closer to the consumer may reduce the voltage drop in the lines and be even more beneficial.

Would expect you to use the nominal voltage for these calculations. ie, 240V. Up to the network to be designed for the variance.

100% though knowing this country the 'smart' solution requiring 24/7 internet connectivity is what will get proposed at some point.

This is exactly what's being proposed by the grid (see the link I posted earlier). Reducing the minimum acceptable voltage to 207V. Modern equipment shouldn't really care about the voltage being that low (the minimum voltage in Europe is 207V and almost all electronics we have bought in the last 30 years have been designed to work in that market). Link suggests a 4% reduction in resistance heating output, slightly dimmer lights. Most tricky issues being non-inverter driven motors and UPSes with to high a brown-out setting (likely can be adjusted).

... Huh? This is what I was proposing which I think you just called unnecessarily complex? Am I misunderstanding something?

It's not a gift. It's part of the value of the home. Sure there are buyers out there that don't value it, but plenty do and the number that do value it will only go up as EVs become dominant. If you hold on to your property for 5 years, the odds are the buyer in 5 years will have an EV/PHEV or be actively planning to get one so they will see the value. In the meantime before you sell, having a charger already installed means that it's available for guests and also lowers the bar next time you replace your car and unless you are a committed petrolhead then EVs are likely to be the best choice when you do so. (As I said earlier the rate of improvement and cost reduction in EVs means that the reasons not to get an EV are vanishing fast). I get the argument that compared to other costly building regs requirements that we may not personally care about (of which there are many) that EV chargers are very easy to retrofit once the wiring is in place and therefore shouldn't be mandated. But rules are inevitably compromises and it's better to have a simple rule that says 'new builds must have car chargers' than to say 'all new builds that will be sold within 5 years, rented out or can reasonably be expected to need to accomodate an EV within 5 years must have chargers'. There are alternative ways to get to the same result but I'd guess they are all much more intrusive and costly.

Changing grid frequency is how the overall grid responds to load as frequency directly affects power generated due to the spinning generators that make up most of the grid. Software driven inverters have more flexibility. They are not constrained by big rotating turbines and generators. So I believe it is possible to inverters to choose how many amps to export independently of the frequency and therefore have a configuration option to have a voltage level where output is tapered off that is set below the max voltage trip. Given our grid runs quite close to the upper limit in many places the scope for this currently may be limited, but there are plans to change the acceptable voltage range of the grid (https://www.efixx.co.uk/Articles/Proposed-Changes-to-UK-Mains-Voltage-Limits-Explained) and if that happens the the average grid voltage might drop. This would give more room to inverters to generate in the first place, but might also give room for regulations to support sensible production reduction above say 250V to produce a more stable grid when lots of inverters are online at peak times. Wouldn't hold my breath for it though (would seem like the sort of thing that would already have been proposed to align with the voltage change if it was going to happen).

Is there anything you haven't done?

Not sure that's right with switching inverters unless programmed to do so. Got anything to back it up? Their internal voltages will be higher than the grid limit, their limitation will come from the voltage seen on the grid line. So they should be able to output the full current up to cut off.

I'm not, but Ohme chargers are £415 + vat and if you are building a new house you don't pay VAT and your electrician bill overall is significant. The standard installation charge includes the wiring that this thread as talked about as the middle ground. My statement is that if you are adding the wiring anyway, then adding the charger shouldn't cost much more than the cost of the charger. The electrician is there anyway running the cables. It may be that you've got caught out here and didn't initially plan on installing the charger and now getting people back to do so is expensive. Obviously that's unfortunate and not a great situation, but it's not the general case.

It's not quite that though. Depending on the situation is equivalent to 'I'll pay for a taxi/train ticket to get you to my place'. If it's a child coming to visit then maybe it makes sense. If it's a contractor coming to do work for you, it doesn't. It's nice to be able to offer the generousity if you have the means but even semi regular charging by guests could be a substantial drain on some people*. Especially as the bills tend to come much later so the scope for running up bills and not seeing the impact until months later (when the electricity company revises your direct debit). * This is a self build forum that has a very specific audience who are much more likely to be knowledgable about these things, have solar, are relatively wealthy so the impact of charging might be less. But in a world where the EV charger is a legal requirement for any new property, plenty of people who know much less, are less wealthy, etc, will be living in places with EV chargers soon. So with that in mind, my view is that if you drive an EV and you ask if you can charge your EV at someones house you should always offer to pay (generously) for the priviledge of charging and only accept free charging if very confident the person offering understands what they are offering.

I'm at that point when I'm spending time thinking about parents increasing needs and having homes prepared for future accessibility needs seems completely sensible. In many ways it would be good if all homes had to be built with this in mind as retrofitting a building not designed for it can be much more troublesome/expensive at what may be a very stressful time. The regs only require it if the PP says so because requiring it everywhere would prevent some homes being built (mostly tiny starter type homes). I'm generally in favour of less mandates, etc, in regs but this one (and functional EV chargers) passes the bar for me. (I see the argument for just putting the cables in for EV chargers, but the extra cost of installing the charger if all the prep work is done is very small and if it's there it will get used*). * We are at about the point now where EVs are same price or cheaper to buy than combustion (before accounting for fuel costs) and it's only going to swing more towards EVs. China is already making 1500km range, 6 min charge EVs, so the reasons for not getting an EV are diminising rapidly.

That's a pretty stunning change.