As far as I'm aware there really isnt a need to get overtly concerned with it.
if you get an enclosure that handles more than 1 drive, it should state its max power and voltage regulations and if a specific size drive may or may not be compatible.
but i think its a bit too much thinking into it.
As long as they support SATA-II (3Gbps) drives, you should be fine...
I'd recommend putting the external drives and any other of equipment on a surge protector atleast or a good UPS.
ok i dont want to spend too much on a enclosure but want one that can support the 1tb caviar black and not cause it to die and have all the things on the drive to be lost
are these enclosures good for my hdd?
http://www.newegg.com/Product/Product.aspx?Item=N82E16817173040
http://www.newegg.com/Product/Product.aspx?Item=N82E16817182136#spec