I have read some more through the discussion and here are some isolated replies to some things
BS546, re-rated to 16A, without shutters is used in Israel for high power appliances, which draw really near full 16A. This is the case with 3+hp air conditioners, so it is commonly referred to as "aircon plug"
All air cons sold/installed nowadays, and most older ones still in use are permanently installed, so there is a dedicated socket installed for it, and the unit permanently plugged in (unless unplugged for maintenance)
Big units of 3hp+ use BS546 on a dedicated 16A circuit, while 2..2.5hp and lower use standard SI32 (Type H) and not always a dedicated circuit. Many small units nowadays draw on the order of 3A so don't demand much from the installation
Compatibility with other appliances is non issue (you don't want to plug a 3hp aircon to circuits that have other loads on them as it'll trip anyway)
The plug size of BS1363 is not just result of the existence of the fuse. It's just a design thing. BS546 was designed before WW2, before all the copper shortage that led to BS1363, no fuse, almost same shape and size
It would be possible to make a plug not much different from the French (due to absence of external shaped guides, there is a little more free space inside than in Schuko), with just enough space inside to install the same BS1362 fuse
The plug size does not have to withstand 32A if the overload protection is provided by the fuse. The only remaining consideration is energy released in case of a short circuit (which is higher on a circuit made for 32A and with 32A breakers), but this probably wasn't even a consideration back in the day when the standard was designed
The Brits did manufacture other designs of fused plugs, in one of them the fuse was being itself one of the pins, so the plug could be about the same size as the smaller ones of the BS546 variants. The design failed because the fuse was easily getting broken off the plug and remaining stuck (live) in the socket hole
With the flat blades of Australia/China plugs, im thinking how much of the pin metal thickness is reduced to make room for the shroud
I expect that it does make the pins easier to bend/break
I think it also greatly reduces the plug's ability to withstand slight overheating from mild bad conections and overloads
The relatively huge cross section of the plug pins is not needed electrically to carry the rated current (14awg wire can carry the same current....). Electrical connections other than "user" plugs and sockets, like internal interconnects of electrical assemblies often push as much as 50A or higher into similar size pins
The differene is, that there the pins are assumed to be always in good condition, not oxidized, with all conductors properly connected, and those connectors are not rated anywhere near the number of plug/unplug cycles that "user" plugs are
But the pin size makes for a good heat conductor, to very effectively draw heat away from the relatively small point of contact where the heat originates. The heat dissipated from the entire surface of the pin (including the parts further away from the contact) and even "pushed" somewhat into the wires, results in much lower temperatures for the same electrical losses
The "neck" created in the metal by the shroud in the Aus/CN plug creates a higher thermal resistance, which reduces the pin area available to dissipate the heat effectively
Schuko/French sockets don't need shrouds on the pins, because the outer socket body is recessed and that acts as a single shroud over the entire connection. It is already closed when the pins make contact
Israeli sockets which i have seen (which survived to my time) originated from designs of just 2 companies, one of which used to make recessed sockets from the start (~1950s is the oldest i seen), the other didn't. (Eventually in the 90s that design was modded to add the recess too). Everyone else copied from those two and later from each other. The plugs are not shrouded, the existence of old sockets is not considered an issue
Europlugs need the shrouds because the plugs are smaller than the recessed face of many other standards they are meant to be compatible with Schuko/French/SI32 so they make the socket's recess ineffective, and are meant to be compatible with Swiss and Italian designs which do require shrouds on the plug anyway. However, they are only rated for 2.5A, so the thermal effects are not significant
Breaker interruption capability
Typical connection sizes in houses :
US :
2x120V 100A = 24kW
2x120V 200A = 48kW
Israel (~1970s aprtment) :
1x230V 25A = 5.7kW
Israel (~1970s private house or 1990s) :
1x230V 40A = 9.2kW
3x230V 25A = 17.2kW
Israel (today) :
3x230V 25A = 17.2kW
3x230V 40A = 27.6kW
The short circuit current is proportional to the rated current, so you can see where it is going
The breakers also have different ratings to different standards :
The 6kA mentioned is according to IEC 60898, which is for "home" use. This assumes a general user without better knowledge of electricity, less maintenance, etc
The same breakers (except some very cost cut-down versions) are normally rated also to IEC 60947 for "industrial" use. This assumes qualified oversight over its use and proper maintenance, including replacing the breaker when required. Under it they can be rated to 10kA, used at higher ambient temperatures than allowed by IEC 60898, and so on
The FAZ6 breaker i brought as example is what i normally use (where 6kA is adequate). It is the "basic" version of FAZ, from Klockner Moeller (acquired by Eaton), the actual design of the breaker originally came from F&G
See in the same link page 149 for the general ratings of FAZ6 and page 102 for FAZ
Most appliances here have the proper SI32 plugs, but when something has a Schuko plug it is indeed common to see it plugged into SI32 socket, working without a ground
The original SI32 design had differently shaped pins (flat, but not as flat as US style, but like Schuko pins somewhat milled down on 2 sides. The other sides still remaining round shape from the initial round pin), and the sockets would not allow inserting a Schuko or French plug with thick round pins. The holes were sufficient to allow inserting a Type C plug (which has a little narrower pins), with which SI32 had been compatible by design
The users would then just drill the holes a little bigger and plug it in anyway, so it didnt achieve anything
In the early 2000s the final stage of SI32 transition to simple round pins came out, and as a side effect it became possible to insert the European plugs unmodified
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