IEC 60099-8 Ed. 1.0 b:2011

IEC 60099-8:2011 covers metal-oxide surge arresters with external series gap (externally gapped line arresters (EGLA) that are applied on overhead transmission and distribution lines, only to protect insulator assemblies from lightning-caused flashovers. This standard defines surge arresters to protect the insulator assembly from lightning-caused overvoltages only. Designs with the EGLA's external series gap installed in parallel to an insulator are not covered by this standard.