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DC Stray Voltage

DC Stray Voltage

DC Stray Voltage

(OP)
Hello,

I am interested in gaining some knowledge on DC stray voltage. I am involved in a project where the question has arisen about the possibility of DC stray currents. The system consists of anodes and cathodes in pvc wells and the DC can be up to 100 volts. There is also a similar setup with AC voltages up to 560 V but everything is grounded so that should be ok. The DC system is not grounded so is it possible to have stray currents.

Thank you

RE: DC Stray Voltage

(OP)
Not a specific question other than can DC stray currents exist which could cause a shock hazard? I am also hoping to educate myself on this.

RE: DC Stray Voltage

Are you sure you really mean stray currents? If you have a PVC substrate, then leakage is very low and there should not be any DC stray currents worthy of the name.

If there's dirt on the substrate, stray currents will increase. I think that is fairly obvious.

But, there are triboelectric phenomena and there is influence from nearby fields that can change voltage/charge. Is that what you are thinking about? The early CMOS circuits were known to be sensitive to external charges and all it took to destroy a device was to pick it up from an insulating surface (that's why the warning symbol is a hand picking something up).

Is that what you are thinking about?

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: DC Stray Voltage

Quote (IEEE: Stray voltage is caused by primary and/or secondary return current, and power system induced currents, as these currents flow through the impedance of the intended return pathway, its parallel conductive pathways, and conductive loops in close proximity to the power system. Stray voltage is not related to power system faults, and is generally not considered hazardous.)


To mitigate the stray voltage, some utility oversize the neutral to reduce the impedance and reduce the earth return current.

I do not remember to see any report of stray voltage in DC electrical system. I hope you are not confusing with stray voltage found in Washington DC. See more detail in the enclosed link (ignore the first part of the video).
. http://www.nbcwashington.com/news/local/282633341....

RE: DC Stray Voltage

Is there a lot of active cathodic protection in the area? That may cause stray DC voltages but generally the voltages will be less than the voltage applied by the cathodic protection panel. Are you sure that it is 100 volts and not 100 milli Volts? That would be more reasonable for cathodic protection stray voltages.

Bill
--------------------
"Why not the best?"
Jimmy Carter

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