I'm looking at wiring a Stiebel Eltron tankless electric hot water heater in a single family dwelling that requires three(3) 50 amp 240 volt branch circuits to the unit. The unit draws 28.8KW

So my question is what to install for the disconnecting means? Under the 2008 NEC 424.19 requires the disconnecting means to operate simultaneously.

Anyone done such an installation?

Thanx, shortcircuit