I see no use for this at a CG that charges for electricity. It could be useful for your own info or using it at a friends or relatives house for re-payment. Other than that, I see nothing but a toy and a waste of money.
If you were on 20amp or wanted to check 110v appliance energy use, then one of these would be the way to go for $25
http://www.amazon.com/gp/aw/d/B000RGF29Q