This appears to be a switch on a high voltage (est. 69KV) line. However, I see no means to trip the switch from the ground; one must use a hotstick. And all three phases cannot be disconected simultaneously in any case.

(Edit, 6:26pm PDT 09-04-08): I received a rather informative email that described how these switches work from the ground without the need for a hotstick and that all three phases *CAN* be activated/deactivated simultaneously; these things are indeed switches after all. :-)