33.040.99 Other equipment for telecommunication systems

Low-voltage surge protective devices - Part 11: Surge protective devices connected to low-voltage power systems - Requirements and test methods (IEC 61643-311:2013)

Components for low-voltage surge protective devices - Part 312: Selection and application principles for gas discharge tubes (IEC 61643-312:2013 + corrigendum Jul. 2013)

Components for low-voltage surge protective devices - Part 351: Performance requirements and test methods for telecommunications and signalling network surge isolation transformers (SIT)

Components for low-voltage surge protection - Part 352: Selection and application principles for telecommunications and signalling network surge isolation transformers (SITs)