Odd voltages

[gazdkw82]

It would be more appropriate to say it eats up the current. The source of the voltage is the mains in series with a high impedance (often the inter-core capacitance of a length of cable) which approximates to a current source. Like earth leakage, if you pull it right down to earth / neutral potential via a lower impedance, whether that is a snubber, an actual lighting load or even a direct connection to earth, a certain current will still flow, equal to V/Xc of the cable capacitance.

We always talk of the earth leakage current because the voltage (from the CPC to the MET) is negligible and the sources approximate to current sources. But in these 'ghost voltage' situations people often say ''I'm reading V volts on my meter' because they were testing for voltage at the time, but it would be better to divide that V by the input resistance of the meter and say 'I'm reading I microamps on my meter'.

Seriously, where do you gain this level of knowledge?

 

[Mini-ohm]

Seriously, where do you gain this level of knowledge?

I did think exactly the same, my brains in bits

 

[gazdkw82]

I did think exactly the same, my brains in bits

It's not common electrician knowledge. This sort of thing is another level.

Electronics background? Electrical engineering background?

 

[Lucien Nunes]

Well yes I'm an electrical & electronic engineer, but most of the science of what is going on here is probably already within your field of knowledge. You sometimes have to take a step back and apply theory that you know in new ways and new situations. For example, you'Il be quite familiar with Ohm's law but you might not have tried applying it to the input of your multimeter. You probably know the formula for the reactance of a capacitor, but you might not have tried using it to calculate the leakage current of a cable from its stray capacitance.

If you like I'll walk through what I saw in my mind's eye when you posted the original question.

 

[gazdkw82]

If you like I'll walk through what I saw in my mind's eye when you posted the original question.

Yes that would be great