Electicity monitor (N Power)

Count the meter light flashes/rotations over a period of time. That will give you a definitive answer.

Philip

Those simple monitors cannot make allowance for power factor and so can only read correctly on pure resistive loads. None of the things you mention are that sort of load. You need a proper RMS power meter to get any sensible readings

It would be simpler to watch how fast the meter was counting, they nearly always have a fraction of kwh digit which you can see changing even at quite low consumption levels.

I really don't understand what extra information a (fairly crude) power meter adds.

And besides, the items together could well be that high when taken together. I've had chordless phones that use half of that, rather inefficient if you ask me. Brian

Bet that kept your lugholes warm!

Any device that takes account of Power Factor must also measure the voltage as well as current. Ergo, no simple clip on device can be accurate. Even at unity power factor because the voltage is not constant, that is another inaccuracy. (It's only measuring the current, voltage is assumed.) RMS has nothing to do with it.

You don't have to stand next to the meter.

If you have a smart meter the displays can be accurate even with odd power factors.

At low levels to get a reliable reading takes quite a while.

One of our meters is 1000 flash/kWhr or so at 1 kW that's 1 flash every (60 * 60)/1000 seconds = 3.6 seconds. At 100 W that's a flash every

They maybe crude but ours matches the meter readings fairly well, I have taken a bit of trouble to get the current transformer carefully installed around the live tails though. I certainly don't trust the low end measuring but overall it's not bad.

The instantaneous reading is handy and if the data is logged and plotted can show how much energy could be considered wasted from some appliances. Like the "keep warm" feature of a kettle or how much the coffee machine hotplate is taking.

"Dave Liquorice" wrote in news: snipped-for-privacy@srv1.howhill.co.uk:

What can you recommend about placing the thing on the meter tail?

May well vary from clamp to clamp. I find that with the (large) CurrentCost clamp the most consistent (I hesitate to use the word "accurate") readings are with the tail passing cleanly through at 90 deg to the clamp with a couple of straight inches of tail either side. The tail being close to the hinge of the clamp. But the most important thing is to make sure they are fixed relative to each other, any movement or change of position will affect the reading. Don't just clip it round the tail and let it dangle and be free to move.