scope:

This part of IEC 62561 specifies the requirements and tests for isolating spark gaps (ISG) for lightning protection systems.

ISGs can be used to indirectly bond a lightning protection system to other nearby metalwork where a direct bond is not permissible for functional reasons.

Typical applications include the connection to

earth-termination systems of power installations,

earth-termination systems of telecommunication systems,

auxiliary earth electrodes of voltage-operated, earth fault circuit breakers,

rail earth electrode of power and DC railways,

measuring earth electrodes for laboratories,

installations with cathodic protection and stray current systems,

service entry masts for low-voltage overhead cables,

bypassing insulated flanges and insulated couplings of pipelines.

This does not cover applications where follow currents occur.