Capacitive Reactance

[mtnelect]

Not a bad overall explanation. But I take issue with one point, that Stray Voltage (typically Neutral-Earth Voltage, NEV) is usually associated with dairies. It is no more common at dairies than at any other farm or rural distribution environment, where metallic neutral runs are long and ground electrodes in the supply system are fewer and farther between. And it can easily occur in residential situations too.

But dairies are much more affected by NEV since cows with their four footed stance are more susceptible to voltage gradients in the earth and even small perceived voltages in the earth or to metallic contacts like feed and water troughs will have a severe effect on milk production.

Should it be called "Stray Current" instead of "Stray Voltage". It's the current that stop the heart, not the voltage.

 

[GoldDigger]

Should it be called "Stray Current" instead of "Stray Voltage". It's the current that stop the heart, not the voltage.

The age old debate! Right up there with ground up or down in its unresolvability and ability to polarize discussion.

I favor Stray Voltage because the voltage is there regardless of whether anybody or any creature is in the area to be affected by it.
The NEV, for example, can be sensitively measured statically, without drawing any significant current. But I agree that the biological effects result from the current when the body interacts with the environment.
But the same measured voltage can be caused by simple capacitive coupling, with very limited available current, while NEV can actually support a much larger current if the target's resistance is low enough. Limited mostly by the earth connection impedance.

 

[mtnelect]

The age old debate! Right up there with ground up or down in its unresolvability and ability to polarize discussion.

I favor Stray Voltage because the voltage is there regardless of whether anybody or any creature is in the area to be affected by it.
The NEV, for example, can be sensitively measured statically, without drawing any significant current. But I agree that the biological effects result from the current when the body interacts with the environment.
But the same measured voltage can be caused by simple capacitive coupling, with very limited available current, while NEV can actually support a much larger current if the target's resistance is low enough. Limited mostly by the earth connection impedance.

I guess why GFCI are measured in ma instead of voltage ?

 

[GoldDigger]

I guess why GFCI are measured in ma instead of voltage ?

The problem GFCIs are intended to solve has nothing to do with Stray Voltage, at least for reasonable length branch circuit runs.

 

[ptonsparky]

Should it be called "Stray Current" instead of "Stray Voltage". It's the current that stop the heart, not the voltage.

You get some pretty blank looks when you tell a dairy owner 'stray current'.

 

[kwired]

Should it be called "Stray Current" instead of "Stray Voltage". It's the current that stop the heart, not the voltage.

without the voltage there won't be any current either though.

 

[kwired]

I guess why GFCI are measured in ma instead of voltage ?

and a GFCI won't respond to stray voltage. It does respond when current strays outside an intended path though.