A fun read!
I feel compelled to say that all British (type G plugs) _have_ to be fused as the ring main has a maximum current of (typically) 30A yet the plug and socket maximum is 13A. So every appliance plug is fused, and the consumer unit has an RCD on most accessible circuits in addition to a circuit breaker.
Some plugs don't make the fuse obvious, but the traditional values are 1A, 3A, 5A, 7A, 10A and 13A (iirc -- for some reason!)
There are actually many features of the British and European wiring system that I think are really quite good. The device is closely related to a "smart meter", which are being slowly rolled out -- the UI is similar to those rolled out nationally, but it's a bit different.
Fuses in plugs in Britain are either 3A or 13A, by regulation. 5A used to be another value, but is no longer used (though replacement 5A fuses are easily available.)
I've never seen 7A or 10A fuses, and I was the kind of boy to rummage through my grandparent's workshops. ..
They are available in the sizes I mentioned, plus 2A – https://www.farnell.com/datasheets/1683350.pdf – and your comment made me actually look up the regulation out of curiosity as I know I have seen some of those other sizes in the lab! The wiring regs are enforced in statute by The Plugs and Sockets (Etc) Statutory Instrument 1994 [1] which mandates the compliance of two British standards, BS 1362 and BS 1363 for fuses and plugs respectively. The exact wording of BS 1363 (at least the version of it I can access) is
> [...] all rewirable plugs shall be marked on the engagement surface with the rated current. All non-rewirable plugs shall be marked with the rated current of the fuse link fitted, which shall not exceed the value given in Table 2 for the appropriate size of flexible cord
Table 2 itself prescribes a maximum fuse rating of 3 A or "(5 A)" [see below] for a conductor cross-sectional area of 0.5 mm^2, and 13 A for all larger conductor areas (0.75, 1, 1.25, and 1.5 mm^2). It is entitled "Rated current and maximum fuse rating in normal use, and load for flexing and cord grip tests related to size of flexible cord"
> [...] The figure in brackets indicates the fuse rating when a non rewirable plug is used with certain types of equipment where the use
of a 5 A fuse link is necessary because of the high instantaneous inrush current
So there we go, I think – we're all sort of right. Thanks for sending me down this rabbit hole!
Ring circuits may have made sense in the past, but they really don't any more. It's basically impossible to test a ring circuit in place - you have to break the connection somewhere to ensure the ring is complete. That's a huge downside. They were conceived at a time when circuit breakers were expensive and wire was in short supply - neither is true now, yet people are still installing them.
The weirdest bit for me was when he ordered a 3am fuse from Amazon, rather than just wandering down to the corner shop for a little blister pack that has 13amp, 5amp and 3amp fuses. Usually just next to the sewing kits
Why don’t you use a 13A circuit breaker in UK? That’s what we do in the rest of the EU, I think.
There’s a main input to the house which usually is around 15A-30A , then we’ve got multiple sublines with individual circuit breakers, typically 10A or 16A.
I just read up about radial vs ring circuits; I had seen ring circuits only in industrial contexts here in Italy, so the fused approach makes sense I suppose.
Probably depends on the country. In Italy we usually employ natural gas stoves and we use natural gas furnaces for heating, so normally you get a 3kw to 6kw max inbound power. I think you can easily get to 10kw, but above that it's quite difficult.
That's interesting. I wonder if that's part of the reason why electric car uptake has been so low in Italy? Most houses here in the UK have enough capacity to run a 7kW charger alongside other household stuff. My house electricity supply must be 50 years old and 80A (about 18 kW) - so it's not even a recent thing. Do people in Italy never have electric showers? How much power do they run to a new house?
From a decarbonisation point of view it's a real challenge - the only current path to low carbon living is through electrification of heating, cooking and transport.
I may add that there is an additional (lesser known) issue.
The "typical" contract is 3 kW, due to air conditioners becoming more common, many people upgraded to 4.5 kW (it was also possible, cannot say if it still possible now, to make a 3 kW contract with an upgrade only during three or four months in the summer).
Very few people (and very large houses) have a 6 kW contract.
The "fixed" part ("potenza impegnata" translatable to "committed power capacity") is a non thrifling part of the monthly (or every two month) electricity bill, so eveyone historically used the smallest possible contract (usually there is a 10% or 20% more allowed for peaks).
The electrical plant needs to be made (and certified) by a licensed electrician BUT (and here is the catch) only up to 6kW the electrician can make (and certify it) without the need of a project by an authorized technician, which adds some costs.
Additionally (of course it depends on the specific area) up to 6 kW it is considered "normal" and it is rare that the distributors asks for compensation (besides the increase in the bill, and an initial "fixed amount" ) whilst when you go up, it is not uncommon that you are asked a sum as a contribution for the works needed to upgrade the distribution lines.
For increasing from 3 kW to 6 kW it would be around 70 € x 3= 210 € + around 50 € + VAT and then around 22 € x 3= 66 €/year (again + VAT).
Stepping up from 6 to 10 (besides needing the project and re-certification) is not unlikely to cost several hundreds or a few thousands Euro.
Anyway, before the issues with the power needed for re-charging, few people have the "luxury" of a parking space or garage, I would presume that this is a bigger obstacle for electric car adoption.
Some plugs don't make the fuse obvious, but the traditional values are 1A, 3A, 5A, 7A, 10A and 13A (iirc -- for some reason!)
There are actually many features of the British and European wiring system that I think are really quite good. The device is closely related to a "smart meter", which are being slowly rolled out -- the UI is similar to those rolled out nationally, but it's a bit different.
Keep exploring (and don't play with the mains!)