Do you know model of light I have?

Thanks for the eBay ID, I was able to find it.

You that...you won't regret it!

That is not that much: The total transformer wights some 100kg or so, include the core, case and oil fill.
They usually use copper only for the rather thin primary, the thick secondary is usually made of sheet aluminum.
We are talking about just 5..10kW, it is not that much.
Well, even the poles wont be able to support much more, when there use to be 2..3 "cans" hanging on a single pole...


True, and correct about the secondary typically being AL.


But it is system tailored for the US geography, mainly the long distances of the "last mile" (in the range of 10km or so).
The European much denser population make the "last mile" way shorter (virtually all below 1..2km), so easier to serve by directly the final socket voltage.
I think these aspect played significcant role in the mains specifications evolution in the past:
The long distances in the US mean the need for the customer point final transformer. That lead to use of more convenient lower voltage for the inhouse installation (mainly the higher efficacy and reliability of incandescents), the higher number of transformers made then the higher optimum frequency of 60Hz (allows smaller, so lighter and cheaper transformers for the same power and losses).



Which is offset by the cyclic loading of those transformers. Because homes typically draw only a few amps during the day and several killo watts for about an hour or two when residents come home pole pigs often swing from little load to a 200 to 300% overload. The over load is done to economize the transformer when subjected to cyclic loading with the thermal inertia of the oil protecting the windings from over heating. But in the end you have thousands of transformers that never realize efficient loading. Energy wasted keeping them practically magnetized then driven in a state where they are essentially a heater.


With 230/400Y however the secondaries can travel 4x the distance and various voltage systems can be ignored (ie a restaurant needing 120/208 while the home across the street wants 120/240) This allows a greater diversity of costumer load and types. Meaning you can mix a business with many homes on a single transformer or bank leading to substantially more steady loading. Instead of a 300% over load, your talking about a 125% peak overload or even a 105% peak over load.         



The higher population density in Europe meant it made sense to use larger HV/socket voltage transformers serving more people, with the "last miles" fed on the final "socket voltage". Because of the high currents there, it was beneficial to use lower frequency (50Hz), to limit reactance related parasitics in the wiring. And to not have these current that high, it made more sense to move to higher voltage, the 3x230/400V was the maximum manageable for common loads like incandescents (even though these were of lower efficacy than the 120V ones), still manageable for fusing, etc.

I don't think 50 or 60HZ has much to do with that. Maybe I'm wrong. 

Today the standards are set, the potential benefit from switching to another one are so little if any it does not make sense to switch.

Didn't stop the Phillipines from doing it.


If something is going to alter some standards, it is the spread of the local power generation and mainly storage in the near future. Because the only low power (below MWh range) storage technologies we have are based on electrochemical batteries, as well as the solar generation are inherently DC, as well as most modern appliances are internally using DC too (induction stoves, direct drive washers, VFD AC compressors, all IT equipment,...) it may make sense in the future to get rid of the many conversions required and distribute directly the DC. But I don't think this is going to happen any time sooner than when these local generation/storage things will really be in wide spread use. So decades from now in the fastest scenario... Today this trend happens only when someone needs battery backup for some home systems (gas or wood burning heater auxiliaries), then the lighting (its power gets so small it allows it) is glued on that and so installed as 12V or 24V DC direct battery voltage...

A single family home, regardless how large, wont still have more than a single stove, single washer and dryer or so. The only thing the larger will need higher power is the temperature management and that operates at all three phases (so 400V) anyway.

Right, so, you would need more then once circuit even at 400 volts. Thus you will not be running more circuits solely upon fear of loosing the entire home.   




Mall is more an industrial installation.
Large apartment high rise has all units distributed across all phases, so effectively runs on 400V. And the number of circuit wont get reduced, as each apartment would need multiple circuits anyway.

And what factor would force the same number of circuits when a 16 amp 3,680 watt circuit now becomes a 6,400 watt circuit? A fuse board with 6 circuits and 6 single pole breakers will now have 3 circuits and 3 double pole breakers roughly. 



Because of the currents, the PEN busbar needs to be very thick there just for the PE function anyway (voltage drop during a short circuit), usually distributed among multiple channels (so the PEN connection gets redundancy), never heard about PEN problems with those conductor sizes.
Schools need a separate breaker for each class for fault isolation purpose, then the load within one such class is by far not that high (few 100's W for a computer and a projector), so again no benefit from higher voltage. Plus when distributed among the phases, the effective power delivery goes via 400V as well...


What code section requires each class room to have a dedicated circuit? The NEC and BS7671 does not care. I am on the side of any code which does not restrict the number of outlets or rooms on a circuit. Canada has that limit as well as France, very dumb if you ask me.   


It is common for modern electronic thermostats to feature a random delay after power recovery to start the compressor (I won't be surprised it made it into the Codes as well, mainly for US market, where the AC is really everywhere; again a cultural thing...), just to make sure they won't start at once in the district after a power interruption there.
And with the kettles: Given the cultural environment in UK, it really is a problem there. It is indeed UK specific, but it is a problem for them.

Some ACs do have brown out protection, but beyond that if someone wants a 3000 watt kettle or grill they should have it.   

Well, you would be right, if the consumer would be really paying all the costs related to that. This is the main difference between incandescents vs high power tea kettles in UK:
The only thing the incandescents cause is high steady energy consumption. But it does not fluctuate, so easy to manage in the network, the related power generation could be very efficient, so the coal burned and CO2 release correspond just to the energy consumed. The users are billed for that, so indeed there is no other ground for further restriction.
The high power kettles in the UK are far different story: They cause very high load spike (for two minutes at once). In order to prevent network collapse, all generating equipment has to be ready to kick in in advance and able to deliver the power spike for that two minutes. But that means the coal burned corresponds not only to the two minutes of real delivery, but to all the time needed to "warm up" the equipment, so many times more. The problem is, nobody is actually paying for that extra coal consumption and related environmental impact, so it gets distributed over all customers, include those who do not cause such demand spike, quite unfair.
Agree, the true solution would be to let all the "tea makers" really pay for all that (if they want that tea just at that moment, they have to bear all it costs, that only would be fair). But that means really smart metering has to be installed. A simpler way is to restrict the power rating, so reduce the peak power and prolong the time, so make the extra costs (both financial, as well as environmental impact) related to that spike lower (diluting the spike from 2 to 3 minutes already means 50% savings on those extra costs). Yes, hurts those who do not cause the problem (longer wait time), so that is why this regulation should be limited to really where the problem is and only till it gets solved by e.g. the smart metering. But short term there is not much other UK may do to reduce that waste.



Still seems silly to reduce the wattage of kettles over something that may change anyways down the road in terms of the culture of kettle use or the available reserve capacity like pumped storage or ultra caps. 



Well, in a fictional world where both contacts move exactly at the same time, yes. But the real world has tolerances and that means one contact would always be faster and that would be the one taking all the load, because the second would disconnect without any or with already very reduced current.
Two pole MCBs are sometimes made as two single pole MCBs with just a trigger interlink, so indeed cost twice a single pole breaker.

But it doesn't stop manufacturers from turning single pole breakers into double pole breakers more often then not.


But an use on a single phase to N allows the N contact to be made way smaller, so the overall assembly could be made just a bit more expensive than a single pole breaker, so way cheaper than the full two pole system you need for phase-phase circuits. In fact in this way are made many "single module" RCD/MCB combos (that is, what I would use in any home wiring, instead of a common RCD and then many MCBs as many do in an attempt to lower the costs - then a single fault tripping the RCD plunges the whole house into darkness, completely defeating the main purpose of the "many circuit" arrangement)


But think, why do we do this? Why switch the neutral? Is it because the neutral can break? Causing it to become live? If the fear of an energized neutral is so high, why not the over voltage associated with a broken neutral in a 3 phase system? An open neutral is a fire hazard and the cost it can create is substantial.   


Well, actually the US system uses less copper/aluminum.
The key difference is, the "last mile" (so from the substation to your property border) in Europe is carried directly on the 3x230/400V level (then directly feeding the sockets), so needs to be sized accordingly. Here we are talking about 1..2km of cable.
On the other hand the US installations uses 5..15kV for that "last mile", so way thinner wiring with less material and serving more customers, then on the border of your property is a transformer turning that to the 2x120/240V going to your sockets.

And what is done overhead on the NESC side is COMPLETELY offset by what happens on the NEC side. Every single installation uses at least 3-14 times more copper, even at 277/480.


Its not just the lower voltage, but the ampacity restrictions, 80% rule and load calcs for services which force every comparable installation to use substantially more copper and/or aluminum.

A few simple cases:


1.5mm2 is typically rated 16amps and is allowed higher when clipped direct. In the US a 15 amp circuit must use 2.08mm2 (despite using 90*C insulation) regardless of the installation method. 2.5mm2 is typically good for 20amps in Europe. In the US 3.31mm2 is required. Where 4mm2 would work 5.26 is required in the NEC. This goes on for every wire size.


In the UK a 4,500 watt water heater can use 2.5mm2 cable in contact with insulation or 1.5mm2 clipped direct. In the US, code would require 3.31mm2, but because the NEC wants 150 gallon and under water heaters to be considered a continuous load the breaker must be sized at 30amps and the circuit wired in 5.26mm2. 1.5 vs 5.26... 


Aside from the continuous rule requiring feeders and branch circuits sized at 125% of the already restricted ampacities you have load calcs which really take things to the extreme. Services and feeders that will never be loaded to more then 60amps end up being 225 amps. Where a 1000amp main will do code forces a 3000 or 4000amp main along with the conductors to support 3000 or 4000amps.




So yes, US needs larger cross sections for the final 2x120/240V, but only for some 100m or so,
while Europe needs a bit thinner wires, but for 1..2km runs.
Again, I'm speaking about residential installations. Bigger commercial buildings tend to have their own "property border" 22kV->3x230/400V transformers even in Europe, but that is more an industrial installation.


Bigger installations tend to be fed with 277/480, but you have 480-120/208Y transformers all over the place which waste energy and copper considering how over sized code makes them.


Trust me, the US is addicted to copper and aluminum lol.