jes,
What I forgot to say, was that these things, over here in NZ, no matter what size, are invariably fed via some sort of Earth-Leakage protection, normally 30mA for ordinary personal protection, 10mA for Hospitals and other Medical areas.
These types of heaters are becoming more common for use,over here as shower water heaters instead of using the traditional Hot water Cylinder, I hate the damned things,
they are such a nuisance to wire. [Linked Image]