IEE Code of Practice
Plain extension cables above 25 metres fall outside the scope of the IEE’s code of practice which is one reason why many Portable Appliance Testers (PAT) testers do not cater for long cables. The Code requires that the earth bond wire is within 0.1 ohm of its theoretical value and that it will sustain 150% of the maximum load current for between five and twenty seconds, long enough to clear the line fuse under fault conditions. These tests demonstrate that the connection interface is stable and that the cross section of copper is continuous.
The Cirris HiPot testers are based on these criteria with facilities to test and prove cables 100’s of metres long which PAT testers cannot do. They are capable of precision kelvin (4 wire) resistance measurements, measuring wiring integrity down to milli-ohms thereby ensuring (through Ohms law), that the cable can safely pass the rated currents at the rated voltage. Any poor-quality connections will be instantly detected and identified.
Finding intermittent faults
During the low current 4-wire measurement phase, the Cirris’ unique ability to cycle (at high speed) on test, enables all momentary opens and shorts to be logged and reported. Simply move and stress the cable under test until satisfied that the cable is sound.
Cirris provides up to 1,500 vdc and 1,000vac and has detectors for constant leakage to 1Gohm and short-term spark discharge. The highest dc voltage will accept cables up to 10nF rising to 100nF at 100volts. A Cirris tests every wire to every other wire and to the shell and screen.
Find out more about Cirris Testers.