Switchgear unit for switching high dc voltages

An isolating apparatus for interrupting direct current between a direct current source and an electrical device, the isolating apparatus comprising:

• a switchgear unit for switching high DC voltages, said switchgear unit containing:
• a housing;
• a conductor path;
• two connections, including a first connection and a second connection, projecting from said housing and electrically conductively coupled by means of said conductor path;
• a thermal fuse;
• a mechanical contact system, disposed between said first and second connections, and having two contacts which can move relative to one another and can be transferred from a closed position to an open position;
• the isolating apparatus being tripped by means of said thermal fuse, for extinguishing an arc produced when said contacts are opened;
• a moving conductor section;
• and
• said thermal fuse having a melting location disposed in said conductor path and connected first to said contact system and second via said moving conductor section to said first connection, wherein the isolating apparatus being tripped and a connection between said conductor section and said contact system being broken at said melting location when the arc has caused a melting temperature of said melting location to be reached or exceeded.