4kW static load!! well that is your answer.   There are 365*24 hours in a year approx 9000 hours.

The national grid is sized assuming most houses  average something like a quarter  of that in the day  !!!!

(Usually ignoring occasional flights to 10kW for showers that last 15 mins, or the odd half hour of cooking so do not count)

That static load needs to be a few hundred watts at most, not thousands, something big has been left on, or perhaps the neighbours have plugged in a cannabis farm into your garage and failed to mention it to you.

I think the 3 phase part is a red herring, except that the time is co-incident, or something was switched on like a supply to a frost heater or a back-up immersion heater element that had previously been left off.

You need to get the standing right load down and understand exactly what it is.

Start flicking breakers and unplugging things to see where it is going, and report back.

Mike.

A few years ago we received a huge electricity bill one quarter for our holiday home in France. Rang alarm bells as we hadn't been there for a while. When we investigated, it was because we'd left a 2kw oil filled radiator on by accident in one of the rooms for a couple of months. 

So as Mike says, you need to isolate what it is that's using that amount of electric overnight so start unplugging things and turning off circuits to narrow it down.

Really interested in how that turns out so again, as Mike says, please report back to us! 

I'll start tonight and report back once i've got some data ... thx

Thx Mike will start this evening

Crikey!

I thought that our 6,000 kWh/year was bad, but when Mrs P's useless old freezer died, consumption dropped to 4,500 kWh/year.

I still think that's a lot given that we have gas heating and cooking.

One day, I shall get my clamp meter out and check the whole house. Now then, what has been left on for the last 26 years?

Random thought - is the system TT?

Just wondered about an uncleared L-PE fault.

   - Andy.

25,000 kwh is an average load of about 3kw, or after allowing for a normal domestic usage perhaps an EXTRA load of about 2.0 to 2.5 kw.

Likely culprits are in my experience, an electric water heater left on, or with the hot water leaking to waste.

An anti frost heater with a defective or wrongly set thermostat. Any sheds or greenhouses or garage with an electricity supply.

Any close neighbours who might be using your supply, either due to deliberate dishonesty or a simple misunderstanding.

My guess: the kid's mining Bitcoin in the garden shed.... :-)

given he promised to come back and has not, perhaps the supply to the computer has been unplugged....

So, I've now monitored the meter as below and it's tracking to 36,000 KWH annually. More than just a dodgy freezer ... 

Clearly 92-110 KW daily is crazy.

There are three RCDs, I plan to turn one of them off each night for the next three nights. Then IF if drops hugely to switch each fuse off overnight.

Any other suggestions most welcomed.....