I picked up this Kill A Watt device to find out how much power each workstation (PC, monitor, phone) really drew here at work because I noticed that if you go by the rated amps on the back of all the devices we should have melted down about 6 years ago. Luckely most PC’s probably don’t draw 400 watts even if they have a 400 watt power supply, and it turned out a workstation would draw 1-2.5 amps not the fully rated 6 amps.

But now that I’ve got this in my toolbox I know where I really need it: Touring video heavy shows. I’ve been hired to go out with shows, or sending out my own designs for theatrical productions on tour with racks or stacks of PC’s and projectors. And I generally look at the power rating for it all, add it up and request that much power. However It’s not at all rare that I don’t get that much power after all, and it would be really nice to know just how much power we are drawing, and the Kill A Watt tells me that.
It will give you a quick reading on weather the power is running hot ag 120 volts or low at 105 volts. And what your total draw on that circuit is. Now if I’ve got the patience I can balance the draw on my racks into nice tidy 15 amp circuits.

And it turns out there are a whole range of products like this but the Kill A Watt does seem to be the cheapest.