true, hence the double pole. but if you cut a live 10/3 or 12/3, you're gonna get hit by both sin waves, simultaneously. however, the amps are halved, so the bite is more a pop than a grabshitanddieohfuck... burns or blasted holes are more common when shorting a double phase line than single phase 120v.
i own exotic reptiles, they use MUCH more power than the 4kw used in the grow room. the fish thing isn't a stretch, but a guy needing shit for a bunch of water tanks in a trailer? um... fishy? i'd never put more weight on a trailer floor than a single 55g fish tank. that shit will fall straight through the melamine...