What is using 300 watts all the time? -Mystery solved (see post #36)!

stevemcol

I assume these devices clamp round the supply 'tail' to the consumer unit. I hope the display is battery powered or this is going to be difficult.
Switch off the main isolator on the consumer unit. The display should read zero. If it doesn't, it's 99% certain a problem with the power monitor.
If it does read zero, switch on the CU but all CBs off, should still be zero.
Switch on one of the lighting circuits; should still be zero. If not, try another.
If still zero, switch on one light switch with bulb on of known rating. If the power displayed is within 10% of the bulb rating, chances are the power monitor is roughly accurate. You can now track down the mystery power drain.

In summary, if the monitor is not Zero with the CU switched off then there's no point worrying anything else. It's the power monitor.

buglawton

You got it in one there... the reason I could not switch the last breaker of doing my test some weeks ago was that the display goes dead! But watching the dial creep round gives a real world idea of consumption too, only not so convenient.

asbokid

victor2 wrote: »

I got one off fleabay for around a tenner. There's still quite a few available - just search for something like "electricity usage meter" on the site.
They are good for individual sockets, although obviously can't tell you the usage of something without a plug on it. They can be a bit of an eye opener, even if you do risk turning into an electricity miser!:)

The plug in socket is going to be more accurate than the induction-based Wattson clamp.

The socket can accurately measure voltage and current, whereas the Wattson makes a blanket assumption of 230v.

The EU harmonisation of 2008 states that domestic supply must be 230 V ±10% (207 V to 253 V).

That introduces quite a margin of error in the power calculations.

spud17

asbokid wrote: »

The plug in socket is going to be more accurate than the induction-based Wattson clamp.

The socket can accurately measure voltage and current, whereas the Wattson makes a blanket assumption of 230v.

The EU harmonisation of 2008 states that domestic supply must be 230 V ±10% (207 V to 253 V).

That introduces quite a margin of error in the power calculations.

Think you may have hit on my problem, my plug-in meter shows my voltage as ~248v.

Messed around a bit more found if I re-set everything it read zero, flick on the light, correct, off, back to zero. But if I loaded it up for a few minutes it would only return to 45w.

Cheap nasty thing, and not to be relied on.

hc25036

Thanks to all for the advice! Had the house to myself this morning and worked through it logically - and it's a shame that the guys that built our extension didn't work logically when they did the wiring!

Narrowed the "excess" 300 watts down to the kitchen circuit, turned off the fridge/freezer, oven clock, boiler, radio - everything I could find and still had 280 watts used. Scratched head, wandered out to the garden through the extension and noticed the pond filters were still running! The external sockets had been wired via the kitchen circuit and not the extension circuit...

Turned them off and use was down to 20 watts, which is probably the error range of the device. Must say the filters are using more power than I expected, so will look at what is going on there.

Thanks to everyone for your help and advice!

victor2

Good you tracked it down.
Expensive pond you've got there though!

hc25036

victor2 wrote: »

Good you tracked it down.
Expensive pond you've got there though!

Now you mention it, I reckon it's about £160 a year. There are two smallish ponds and they are both wildlife havens though.

John_Gray

Looks like something to ponder on... :rotfl:

hc25036

:T..and I shouldn't be koi about it either....

(this could run and run!)

rmg1

There really should be a time and plaice for jokes like this!