If by "hub" you do mean switch, then yes, you can have a switch behind another switch.
Yes, you are correct, it is a switch. Ok, good to know, I'll go pick up another one, thanks.
I use a plugwize system to monitor power usage
I neglected to clarify that I could not find an affordable meter for 240volt
US plug style that is cheap, I did find a few (like you linked) for Euro-style plugs.
They mass product the us kill-a-watt.
You bolded the wrong part of my quote, it's the 240 volt that's the kicker. KAW is only 120v, and I have 2 of them also.

For example, I found this 240v one which I could use, but it's $90 and I'd have to split open my nice an tidy 10ga cable and mount the meter to the wall, not sure it's worth all that.
