Re: What is your electrical usage per month at your home? When do the cops come?lol
I have heard of police in the US using high electricity usage/high IR signatures to get a warrant for search. However unless they had another reason to look in your direction in the first place, that probably wouldn't happen. Also, unless you have a marijuana farm next to your mining farm, nothing would be confiscated. 
It happened to someone on the forums right here. They had a helicopter with thermal cameras so see if all the heat is located in one room and then got the search warrant.
The Supreme Court ruled that using an infrared camera on people's homes is illegal.
I don't think high electricity usage is a sufficient condition for them to bust your door down by itself.
http://bitcoinminer.com/post/5762837023/cyber-bitcoin-mining-grow-ops