Date   : Sat, 11 Mar 2006 00:53:52 GMT
From   : Pete Turnbull <pete@...>
Subject: Re: Them pesky case stickers (was 1MHZ SCSI/ATA board.)

On Mar 10 2006, 19:51, Annihilannic wrote:

> Can you get a widget that goes between an appliance and the wall
socket
> to measure its power consumption?  I have a multimeter, but am
reluctant
> to go around measuring 240V AC currents in series by sticking wires
into
> sockets or similar!  And I'm not sure how much a little digital
> multimeter can handle in series like that?

My Fluke DMM can handle up to 10A AC.  A better way is to get a surplus
wattmeter -- like the electricity meter your supplier installed, with
the rotating disk.  You can also use a clamp meter, a device with a
ring-shaped clam on the end instead of cables.  It uses magnetic fields
to measure the current, usually via a Hall effect sensor.  Many are
designed for electrical engineering, and will only resolve down to
about an amp or so, but you can get reasonably inexpensive ones
(£60-£120) that will resolve down to the nearest 100mA or even 10mA.
 That's what we use for measuring servers on the UPSs.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York