Metal-enclosed gas-filled switchgear units

A metal-enclosed, gas-filled switchgear unit including at least one busbar system, comprising:

• a circuit breaker pole housing, the pole housing being in the form of a metallic enclosure and having a pole axis;
• at least one upper current terminal and at least one lower current terminal, the upper current terminal and the lower current terminal each being connected to the pole housing by separate insulators, the upper current terminal and the lower current terminal having an upper electrically conductive connection arrangement and a lower electrically conductive connection arrangement, respectively;
• an arcing chamber extending along the pole axis in the pole housing and in a breakable electrical path between the upper current terminal and the lower current terminal;
• and
• the lower connection arrangement including a contact subassembly having an electrically conductive contact ring electrically connected to at least part of the arcing chamber, the contact subassembly being arranged in the interior of the pole housing and the contact ring being concentric with the pole axis.