I want to use a DC Water Heating Element as a Dump Load for a 48v/30amp
small wind turbine and/or photovoltaic set-up. Say I=3Fm looking at an
absolute maximum power output of 1.4kW

Out of interest, since you`re talking about 3.5kw output, can you tell
me what protection system you`re using ? (G83/1 applies I think, but i`m
not sure whether you`re looking to interconnect back to the mains
network)