Induce Voltage in Multi Core Cables

Thanks i will carry out the tests and inform you accordingly.

Further can you tell me what are the long term effects on the electrical network?

once again thanks for your support.

Regards

AA

The effects will be nil/zilch/nada/nothing.

Thanks.

what if i change the neon bulb with filament bulb should i still use a 250k ohms resistance?

Changing to a filament could be beyond the current drain ability of the driving circuits. the Neon lamps have no direct connection across their leads, and so present no loading to the circuit until they fire. Changing the lamps to filaments would require pre-analysis to be sure the system would not be corrupted by the new loading.

...and it's also called High Impedance Digital Voltmeter Syndrome.

Change to a cheap-and-nasty moving coil analog meter and see if the voltages are still there. There's GBP£1 resting on the outcome.

Follow Slack's good advise. Or cut the cable in 1 inch pieces?

Yup... I agree with the other postings.

If this happens when you energize one conductor only, it is no doubt capacitive coupling.

If you are introducing 220VAC(L) to one core where is the reference for the other end of your meter? Ground perhaps or a common neutral in another cable?

These measurements of induced voltage in the other cores are these also relative to the same reference?

....and you are using neon lamps?

Terminate all free / unused cable cores with 100k Ohms 2W resistor to earth / ground.

This is a common issue with low voltage control cables that have been pulled/installed in the same cable tray and/or conduit with medium voltage or high-current LV load wiring.

If adding the capacitors and resistors do not clear up the "glowing" issue you will have to replace the control cables with shielded cables and earth/ground one end of the drain conductor.

Disconnect all unused cores, especially if they are connected to high impedance inputs in control units in the MCC. The forum cannot see what these are.