Determine the electric cable of rated voltage to and including 600/1000 V required to maintain circuit integrity under fire conditions.
• Reference Standard
IEC 60331-21 – Test for electric cables under fire conditions Circuit integrity
• Test Detail
1. The sample shall be a piece of complete cable not less than 1200 mm.
2. Connect each conductor of sample to a separate phase of transformer output with a 2 A fuse or circuit breaker in each phase.
3. Switch on electricity supply and adjust the voltage between phase to the rated voltage U ( or in the case of single core cable to the rated voltage to earth, U0)
4. The burner shall be aligned with the test sample. Light the burner and adjust the air and gas supply to achieve the temperature of 750-800oC. Continue the test for a period of 90 min.
5. After the flame shall be extinguished. Cable shall remain energized for 15 min.
• Performance Requirement
No fuse shall be ruptured nor any lamp extinguished during the period of test. If the sample fail to conform this requirement two further samples shall be prepared and tested and both shall conform this requirement.