Connection to a 400-volt electrical system for three phases. This allows you to use higher powers. The system used in theatres includes three phases, one neutral and one earth, so to be taken 3 times 230 volts between neutral and respective three phases.
Translation:
Italian: Allaccio trifase
German: Stromanschluss dreiphasig
Bulgarian: връзка трифазен ток
Norwegian: Elektrisk tilkobling, enfaset