A view on internal arc testing of Low Voltage Switchgear

Safety and downtime are the critical factors in petrochemical installations. In this respect, possible internal arc faults have also become a more important issue in user´s specification, dimensioning, operating and maintenance of Low Voltage Switchgear and Controlgear Assemblies. Preventing internal arc occurrences in switchgear assemblies is of paramount importance and an increasingly more important consideration for the design engineers. The paper compares the user´s perception of Arc Proof switchgear against the manufacturer´s way of marketing it´s Arc Proof switchgear. This results in an assessment of the guide for testing under conditions of internal arcing - the IEC/TR 61641 - and suggestions for evolving this Technical Report in order to match the user´s and the manufacturer´s perception. Furthermore the paper gives a manufacturer and test house perspective on the practical value of the internal arc testing, and how the results are assessed and interpreted in order to conclude that a design is arc proof. The latter is in the perspective of safety during operating and maintenance. Conclusions: for the user there is a need for more stringent rules in testing, possible classification and clearer reports in order to make switchgear of different makes comparable.