On Sat, 18 Mar 2017 12:05:12 +0000, NY wrote:

200A per phase at 400V (240V phase-to-neutral) doesn't sound very high.
We have a 60 A "company fuse" and I presume our neighbours do too. With
an electric fire (3 KW), an electric shower (maybe 8 kW) and an electric
oven and hob (maybe 6 KW), you'd be getting towards that limit but still
remaining legal. Now imagine lots of people roundabout doing that.

It's called Diversity. The DNO's know that everything will not be plugged
in at the same time, so their network will cope for the vast majority of
the time (and time has proven this, as there are very few blackouts
caused due to DNO substation fusing blowing).Short term overloads dont
stress the system too much, as can be seen on christmas day - when 50% of
houses have their ovens on etc - but 50% of them are gas,then the oven is
not on full power apart from the first 5 minutes, so the load isnt as
much as you think
I was told the typical demand for each house when the network is designed
is around 5 to 10 amps.That'd give 120 houses to one substation feed at 5
amps - that seems about right.