Turn on / off electrical radiator (400V)?

Today I have electrical radiators in my house which are connected between two phases (=400V) There is neither nul (N) not earth (PE) wired to the radiators, only all 3 phases (L1, L2, L3) and each radiator is connected between two phases.
Is there any chance to control this by OpenHAB, e.g turning the two phases on an off through a Zwave device?

Relais and Z-Wave Aktor?

Please let your electrician do that! 400V are not a toy!

Thanks for your answer. That is the next best solution.
But is there any switch (Zigbee / Zwave / …) which can handle 400V directly? Like this http://qubino.com/products/flush-onoff-thermostat/ , just for 400V?

No … but a ZWave (or other) Switch can turn a Relais for 400 V on and off … and the Relais turn the radiator on and off …

… , but then I need the starpoint (=Nul = 230V) at the radiator, which currently is not there.

But somewhere the lines come from, in the best case from the house distribution. In the house distribution is also N and 230V for the relay available. You should not even start tinkering yourself. Please order an electrician, he can show you all the solutions and connect!