The website formerly known as Twitter has never cared about the username part of the URI; it only looks at the status number and will redirect you to the canonical version if it wasn't.
> Answer #1: Many UK RCDs/RCBOs are actually single-pole devices and don't disconnect the neutral.
This is not correct; all type AC and type A RCDs used in British consumer units disconnect the neutral as well. Some RCBOs do not disconnect the neutral and this is a problem in some circumstances. The datasheet I linked for Wylex NHXS1 RCBOs explains that these ones do disconnect the neutral.
> Answer #2: It looks like some/many one-module wide UK RCBOs _do have_ electronics in them [...] but if backfed for longer than the disconnect time that might be enough to toast the solenoid or the driver
This is correct. For an example of this construction in an RCBO, see [1]. This illustrates that if the supply is connected to the "To Load" part of the schematic (toward the end of the video), as it would be if the supply is a solar PV inverter with battery storage, then it can continue powering the electronics and be shunted out by the thyristor after it has supposed to have tripped, very quickly burning itself out.
Bidirectional RCBOs are not designed in this manner. They have more complicated circuitry that makes them more expensive to manufacture, but are absolutely required in situations like this if you don't want your protective devices to burn and/or explode when they operate.
> Notably neither of these has anything to do with the direction of power flow.
Yes it does, because if the power is flowing backwards to how they designed it, that is backfeeding it, keeping its circuitry powered after it should have been disconnected.
Yes they are. Current alternates direction, but power usually only flows in one direction, from the input terminal (from the bus bar) to the output terminal (that the circuit is wired into).
If the circuit will be supplying power too (e.g. battery storage, an EV and EVSE that supports powering the house from the EV, etc) then you need a bidirectional RCBO.
People with no differential fault protection need not worry about any of this, they'll just be killed when it goes badly wrong.
EDIT: To say nothing of people with unidirectional electricity meters; plugging these into those setups will get them prosecuted for electricity theft. All SMETS 2 smart meters are bidirectional; you'd best check your meter if it isn't one of those.
Between the phasing out of analog meters (the latter half of the last century) and the introduction of smart meters (2010), a lot of electronic prepayment meters produced for the UK market would set a tamper flag if they detected power flowing backwards through them, as a proxy indication of an attempt at electricity theft. These meters will refuse top-ups in this condition, requiring you to contact your energy supplier to sort it out, leaving you without power until you do and then exposing you to scrutiny when they arrive.
Pre-smart non-prepayment electronic meters (for those with old meters, still submitting manual readings, and paying by direct debit) will be fine. Most of these meters, and all smart meters, are inherently bidirectional, because they maintain 4 counts (energy imported and energy exported, in kWh and kVARh) and your energy provider will do all the necessary math to figure out what to actually bill you for (residential customers are not billed for kVARh usage).
The UK government in 2011 announced plans to have 50 million smart meters installed by the end of 2020. In typical overpromise underdeliver government fashion, they didn't even achieve half of that; by then, only 23.6 million had been installed, and of those, 4.5 million had stopped working because they were initially (and stupidly) designed to be tied to a specific energy provider and the customer had changed provider. This even affected me.
Nevertheless they'd still accurately track energy consumption and export even if they'd lost their reporting capability, so you have nothing to fear here. This situation has been rectified at the redesign stage with provider-independent SMETS 2 meters, and all SMETS 1 meters still in service have been hotpatched to bring them into line (restoring their smart functionality regardless of provider).
Even today (well, as of last September), this number is only 40 million, with only 36.7 million of them actually working as designed (reporting readings automatically).
This leaves up to 16 million properties with a meter that may stop working and expose you to a theft investigation when you obtain generation capacity that even momentarily exceeds your usage (for example if you have a dual RCD board and one of the RCDs trips, taking out half of the circuits in your home, but not the one the inverter is plugged into).
Realistically the true figure is probably around a quarter of that; prepayment meters were very popular among the renting population of the time, and those who wanted to track their energy usage carefully and only pay for it with cash as and when needed, and sometimes people had these meters forced upon them by suppliers after the customer had demonstrated poor payment history, but they were far from the norm.
Average home owner buying plug-in solar at a supermarket isn't going to know or care about any of this. They'll just plug it in, and it will work, until one day maybe it doesn't and their supplier opens a theft investigation.
I feel like the meter suddenly "breaking" is the substantially larger inconvenience. Presumably the supplier will raise an eyebrow at the flag, glance over the place, see the solar setup and get on with life. At least one would hope. They must have seen this a time or two by now after all.
The kind of meters we used to install 50 years ago would turn backwards if electricity flowed backwards.
So if you spent a week with the meter connected normally, then you swapped the input and output cables around for a week, the meter would be back at zero. Free electricity!
They used anti-tamper seals to make it more detectable, but there are ways around that sort of thing.
That’s an RCD, not a breaker. Guess the English still insist on using nonstandard terminology, like “lift”, “bonnet”, “torch”, and, apparently, “breaker”. Oh well.
This is not an RCD, it's an RCBO. It combines the functions of an MCB (Miniature Circuit Breaker) and an RCD (Residual Current Device) in one device, as specified by BS EN 61009 (Residual Current Operated Circuit Breakers with Integral Overcurrent Protection).
> > AI training might be copyright infringement. But there’s no cases or laws to establish that.
> In September 2025, Anthropic agreed to pay at least $1.5 billion to settle a class-action lawsuit over using roughly 500,000 copyrighted books from "shadow libraries" to train their Claude LLMs.
Yes, but not because they were training LLMs with it. The judge in the case found specifically that training the LLMs on the copyrighted material was not copyright infringement; the only copyright infringement Anthropic had committed was acquiring the material itself. In other words, if they had legally bought all of the books they used, they would have been able to train their LLMs on them with no recourse from rights holders.
I also drew parallels to the Uberlingen mid-aid collision, but for a different reason.
The mid-air collision occurred because the Russian air crew maneuvered contrary to their TCAS instruction (it commanded them to climb, the controller ordered them to descend). They were not trained that TCAS is the ultimate authority in this situation; it exists precisely because the controller has already failed in their separation duties, and if you have TCAS giving you a resolution advisory, your aircraft is no longer under ATC control and you must ignore any ATC instruction to the contrary. The other aircraft was correctly following its TCAS instruction (descending) because their crew was trained in this. Both planes descended and still hit each other.
In this case, KLGA has RWSLs (Runway Status Lights), including RELs (Runway Entrance Lights) on taxiways, that behave like traffic lights on roads. This too is completely automated and is the last-ditch resort for when a controller has already failed in their separation duties. This system processes transponder data of nearby aircraft and determines whether an aircraft is about to take off (is on the runway and accelerating) or land (is approaching the runway and descending). In either case the RELs go red automatically, and the controller cannot override this.
The driver of the ARFF probably [1] placed more emphasis on the controller's clearance to cross than the lights telling him to stay put, in exactly the same way that the Russian air crew placed more emphasis on the controller's instruction to descend than their TCAS instruction to climb, not realising that they were maneuvering contrary to the thing that exists specifically to prevent these accidents.
EDIT: I am not assigning blame to the controller here. They are human, and humans make mistakes. That's why these systems exist. Having one person handle an airport the size of KLGA is an accident waiting to happen.
[1] Obviously this is unknown at this point, and is something the NTSB will investigate. The system could have been down for maintenance for example.
Generally speaking, there are two levels of crime in the US; misdemeanors and felonies. Both will land you with a criminal record, but a misdemeanor-only record will not show up on some standard background checks and does not remove your right to bear arms or vote, for example. Felonies are much more serious, and generally mandate a minimum prison sentence of 1 year unless plead down, while the sentencing for misdemeanors generally caps out at a year and typically just gets reduced to fines and community service, or a short stint (e.g. a couple weeks) in the local jail instead of a prison.
In some states, first offense non-violent felony convictions (e.g. exceeding the speed limit while fleeing police in a vehicle) can be expunged from your record when you turn 21 (if you were convicted and served out your sentence before turning 21). Otherwise felonies generally stay with you for life.
reply