This part of IEC 62561 specifies the requirements and tests for isolating spark gaps (ISGs) 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 electrodes 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.

Applications where follow currents occur are not included.

Extra requirements for the components can be necessary for LSCs intended for use in hazardous atmospheres.

NOTE 1 In CENELEC member countries, testing requirements of components for explosive atmospheres are specified in CLC/TS 50703-2.

NOTE 2 Testing of components for an explosive atmosphere (as defined in the IEC 60079-10 series) is not covered by this document.