DIN EN 60099-8:2011-11

This standard covers metal-oxide surge arresters with external series gap (EGLA) that are applied on overhead transmission and distribution lines, to protect insulator assemblies from lightning-caused flashovers. The external spark gap may therefore only respond to quickly rising surges. For all power frequency voltages and slowly rising surges, the spark gap shall not respond. Considering the particular design concept and the special application on overhead transmission and distribution lines, some unique requirements and tests are introduced, such as the verification test for coordination between insulator withstand and EGLA protective level, the follow current interrupting test, mechanical load tests, etcetera. Designs with the EGLA's external series gap installed in parallel to an insulator are not covered by this standard. The responsible committee is K 441 "Überspannungsableiter" ("Surge arresters") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.