Characteristics of 400 V dc plug and socket-outlet for DC distribution systems

This paper reports test results and reviews for the developed plug and socket-outlet applied to the 400 V dc power systems expected to improve energy efficiency in communication sites, data centers, commercial buildings, and smart energy systems. However, there are some safety issues to use 400 V dc power. The plug and socket-outlet has a unique mechanism based on combination of a permanent magnet and mechanical contacts in the limited small space. The mechanism should solve the problems such as both arc extinguishing and protection against electric shock known as critical DC power issue for a long time. The results of an investigation of inrush current also are reported, including current size, effects and testing methods, as one problem in the construction and operation of 400 V dc power distribution circuit.