The European standard that formerly governed surge protective devices connected to low voltage power distribution systems has been withdrawn, and its subject matter is now carried by the current part of the series. It remains relevant for two practical reasons: a large number of devices installed in European buildings were approved under it and their certificates and declarations continue to reference the withdrawn designation, and the structure of the current standard is descended from it, so a reader comparing an older report with a new one needs to know how the test programme changed. The document defined the characteristics by which a device is described and compared, including the maximum continuous operating voltage, the discharge currents, the voltage protection level and the temporary overvoltage withstand, and it combined the determination of the protection level with progressively severe impulse current tests, a thermal stability test and the verification of the disconnector. New designs should be assessed against the current part.