Air insulated switch with very compact gap length

A grounding switch comprising:

• a solid insulation housing;
• an outer grounded semicon layer on an external surface of the housing;
• a cylindrical fixed electrode extending into one end of the housing and being encapsulated within the solid insulation housing, the fixed electrode having a center bore;
• a ground electrode positioned at an opposite end of the housing from the fixed electrode;
• an air gap formed in the solid insulation housing between the fixed electrode and the ground electrode;
• a movable electrode slidably positionable within the air gap and the center bore to electrically connect and disconnect the fixed electrode to and from the ground electrode;
• and
• an annular shielding electrode electrically coupled to and encircles an end of the fixed electrode proximate the air gap, the shielding electrode shaping an electric field generated by the fixed electrode to be mostly contained within the solid insulation housing, the annular shielding electrode includes a cylindrical body portion, a protrusion that extends from the cylindrical body portion towards the ground electrode, and a rim coupled to the fixed electrode.

A grounding switch for providing an electrical connection to a ground for a high voltage cable in an underground switchgear, the grounding switch comprising:

• a fixed electrode;
• a ground electrode spaced from the fixed electrode;
• an air gap formed between the fixed electrode and the ground electrode;
• a movable electrode slidably positionable within the air gap to electrically connect and disconnect the fixed electrode to and from the ground electrode;
• and
• an annular shielding electrode electrically coupled to and encircles an end of the fixed electrode proximate the air gap, the shielding electrode shaping an electric field generated by the fixed electrode, the annular shielding electrode includes a cylindrical body portion, a protrusion that extends from the cylindrical body portion towards the ground electrode, and a rim coupled to the fixed electrode.