Funny reading on Maplin energy monitor

moobax

So I got one of those energy monitors off eBay, the Maplin version. When I plug it into a socket without anything connected it reads 00W for a while, but after 10-15 seconds it changes to 04W, and 0.03A. Is this normal or is something wrong?

Cheers
Ben

Sprintblue

sounds like it is doing it's job ... maybe something else is on and you don't know it .. or indeed the device monitors what is uses ...

Geoff_W

No, it's not normal - mine always reads zero Watts & Amps if there's nothing plugged into it. It will, of course, show the Voltage.

Does it do this in every socket in your house? Are you able to check it at another house?

If it still shows a reading wherever you try it, then I'd suggest it was faulty. If it only does it at your house, I'd get an electrician to check out your wiring!

Geoff

moobax

Geoff_W wrote: »

If it still shows a reading wherever you try it, then I'd suggest it was faulty. If it only does it at your house, I'd get an electrician to check out your wiring!

Thanks, yes it is the same wherever I use it in my house - upstairs, downstairs or in the garage (which I think are on different circuits). Haven't tried it elsewhere. But could it actually be the house wiring?

Cheers
Ben

espresso

moobax wrote: »

So I got one of those energy monitors off eBay, the Maplin version. When I plug it into a socket without anything connected it reads 00W for a while, but after 10-15 seconds it changes to 04W, and 0.03A. Is this normal or is something wrong?

Cheers
Ben

Something wrong as 0.03A at 230V would be 6.9W. Read the specification of the device, although it's on load readings that matter. What happens when you boil a kettle of know wattage?

moobax

espresso wrote: »

Something wrong as 0.03A at 230V would be 6.9W. Read the specification of the device, although it's on load readings that matter. What happens when you boil a kettle of know wattage?

You're right that 230 x 0.03 is 6.9, but it's more complicated than that when it comes to determining power with AC. The meter read 6VA (apparent power) and 4W (real power).

http://en.wikipedia.org/wiki/Power_factor

However, I've decided to return it for a replacement. I'll let you know what happens.

Ben

espresso

moobax wrote: »

You're right that 230 x 0.03 is 6.9, but it's more complicated than that when it comes to determining power with AC. The meter read 6VA (apparent power) and 4W (real power).

http://en.wikipedia.org/wiki/Power_factor

However, I've decided to return it for a replacement. I'll let you know what happens.

Ben

Yes my plug in energy monitor does give a power factor reading. Often multimeter's will give odd readings when not connected. The important thing is to try an on load test with a device of known wattage.