Abstract: A device for connection to lightning arresters isolates the grounded lead and contains the resulting spark or arcing flame, including any hot particles generated when ground disconnection is made due to excessive current flow through the arrester. A central spacer member is screwed onto the existing ground lead terminal of the lightning arrester and contains an arc extinguishing channel with an internal fusible link adapted to melt in an overload condition. A shielding cup surrounds the central spacer member for containment of sparks and arcing, and a ground lead connector wire extends from the internal fusible link to a new ground lead terminal at the exterior of the shielding cup, for connection to a grounded lead.