On Sat, 28 Mar 2015 10:09:55 +0000, wrote:

Which being about domestic smart meters might not be relevant to
3 x
300 A supplies (is that 300 A per phase 3 phase supply?).

I think it's 100 Amp per phase which if they are balanced gives 72kW

I have never been able to get my head around 3 phase and power. 100 A
per phase fully loaded and balanced (ie no neutral curent) is surely
415 * 100 = 41.5 kW per phase * 3 = 124.5 kW total?

72 kW at 240 V is 300 A, but 240 is the phase to neutral voltage, 415
being the phase to phase. Ah, light bulb moment, delta v star
wiring...

The reason for 3 supplies is that above 100A direct current monitoring
meters are not available and you get complications with peak power and
half hourly tariffs.

I vaugely remember something about a TV studio supply, if the studio
wasn't working it took naff all but working would push things to the
100 A / phase (notional) limit. Mainly because the the cameras
(Philips PC60's) wern't very sensitive, light levels high and so was
the heat, all that power going into tungsten filament lamps. The
tarrif allowed for this high peak demand without breaking the bank.

As you are on a "traditional" tariff it might be worth looking to see
what savings (if any) could be made by have a "managed" one that
deals with the peaks and half hourly stuff for you. Note this is you
spending an hour on google not giving details to a cold caller...

--
Cheers
Dave.