[VIDEO]http://www.amazon.com/P3-International-P4400-Electricity-Monitor/dp/B00009MDBU/ref=sr_1_1?ie=UTF8&qid=1318453251&sr=8-1]Amazon.com: P3 International P4400 Kill A Watt Electricity Usage Monitor: Home Improvement[/VIDEO]
I just grabbed one of these. This one only goes up to 15 amps, but it's pretty handy to check just how much draw you have on your AC line - and it's only 20 bucks.
There are ones that go higher, but they're quite a bit more expensive.
I picked up one of these at Menard's for $15 on sale. Have used it for all sorts of things in my house (Dyson bladeless fan, dehumidifier, hair dryer), but I bought it with the intention of checking my rack... now, to find time to actually turn it on and play it