Frequency without voltage

[tank]

Could anyone shed some light on what might be going on here, before I cut a trap in the laminate to find out. I have a dead socket on the end of a 2.5mm cable of unknown origin. L-E L-N N-E all 0 volts. Insulation resistance between the ends all 1000M Ohm. No continuity any conductor back to the consumer unit. I even insulation tested the ends via a long lead back to the board bars, 1000M ohm. Yet my glow stick lights up by the cable and when attached my mft reads 0v at 50Hz.

 

[westward10]

When was it ever live, ignore the volt stick.

 

[Lucien Nunes]

Because it doesn't draw any current from the cable, the volt stick can light with even a tiny amount of capacitive inward leakage current caused by the disconnected section running next to live cables or being terminated in the same accessory as live circuits. However the available current is too low for the MFT to measure correctly; although its input resistance is high, it is not infinite and it pulls the voltage down to near zero. There might be enough left for it to sense the frequency though.