IEC 60331-25:1999 Specifies the test procedure and gives the performance requirement, including a recommended flame application time, for optical fibre cables required to maintain circuit integrity when subjected to fire under specified conditions. Describes the means of sample preparation, continuity checking arrangements, optical testing procedure, the method of burning the cables and gives requirements for evaluating test results. Covers electric data cables which have no rated voltage and are used for extra low voltage circuits.