ECN Forum Forums General Topics of the Trade General Discussion Area Phantom Power Consumption

I wonder also how long this has gone on. Only this month, or since he's occupied the house.

I would say, follow up with tracing out those circuits and find out where they actually run and exactly what is connected to each of them.

I have seen mysterious problems similar to this in the past come to a logical conclusion.
In one case, it was a building with a commercial retail shop on the first floor and a small residential apartment on the second floor. The long-term apartment tenant complained to the owner that for some reason, her electric bill this season was suddenly consistently high at close to $300.00 a month during the summer when she was hardly ever even home and was not using any air conditioning.
It didn't take very long to find the problem. Turns out that someone else from the same company I worked for at the time, had installed a new circuit for a dehumidifier in the basement of the commercial area about 6-months before and had mistakenly tied it into the tenant panel, which was located in the basement right next to the panel for the retail space. [Existing installation]
The funny thing is that the electrician that actually did the install was sent back to troubleshoot the problem a couple of weeks before and after some in-depth diagnostics, his answer was that the electricity "must be bleeding to ground somewhere".
Not to say this doesn't occur, but it seems like for many years, I've heard this excuse used all too often when someone can't locate the actual problem.

Go back to basics, check loading on all individual circuits and add the Ampère values up.
These should match the loading on the phase(s) and neutral.

Turn main isolator switch off, after the meter. The meter should stop. ( chances of a mechanical meter being faulty are remote, although electronic meters I wouldn't trust for erratic readings ).

Then one by one unplug or switch off the appliances. It can be a mammoth task, but if you want to check where the power goes, just do it properly.

Bear in mind that a lot of appliances are still on standby when so called turned off, best is to pull the plug from the socket.
Now these days there are a lot off plug in wallwart and SMPS supplies drawing a couple of watts each 24/7, this adds to a reasonable base load.

And sometimes people complain but they forget how long appliances or lights are left on for sometimes.

Just to add and remove uncertainty of earth leakages.

Isolate and test supply downstream of meter, unplug all appliances, ensure that all lighting ccts are off, dimmers switches off.

Insulation test (Megger) the installation as a whole or circuit by circuit at the time. readings should be in the Mega ohm range for the wiring concerned.

Any lowish readings less than 1 Mega ohm on a circuit should be further tracked down to the cause.

Also label all sockets afterwards with a dymo machine and charge customer as an extra service if they want it.

Just my $0.02 worth on this topic.