neutral to ground swell voltage

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tayo

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I have just joined the forum and will like to know why my fluke VR101S is picking up N-G swells in a server room where there is no earth leakage(E-N=0 volts).
There are also multiple transients even after we have installed an INDELEC Surge Arrester 40KA.How dangerous is this scenario.
Thanks
 
There will be a neutral to ground voltage if there is any return current in the neutral which will produce a voltage drop in the neutral. The return current will include third harmonics.
 
The return current will include third harmonics.
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While given the location 3rd harmonics are most likely there but this does not hold true for all neutral to ground voltage measurements.

If you have single phase loads utilizing a neutral/grounded conductor and you do not have neutral to ground voltage you most likely have a wiring issues.
 
tayo said:
I have just joined the forum and will like to know why my fluke VR101S is picking up N-G swells in a server room where there is no earth leakage(E-N=0 volts).
There are also multiple transients even after we have installed an INDELEC Surge Arrester 40KA.How dangerous is this scenario.
Thanks
Click to expand...

What is the magnitude and duration of the N-G transients? What is the initial clamping voltage rating of the surge arrestor? How often do the transients happen in an hour/day?
 
Assuming you have single-phase loads, you had better have voltage between N-G. If you do not then you have serious wiring issues. As far as a TVSS in the N-G mode depends if it actually has any N-G modes installed and where it is in relationship of the service or a SDS. If a TVSS is installed at the service or SDS, the N-G module is completely useless and serves no purpose whatsoever.

Assuming the TVSS is downstream from a N-G bond, then it is even highly unlikely the N-G mode would ever operate, and when it does, you can expect havoc on the downstream electronic equipment.

My guess is the voltage you see between N-G is normal and fluctuates with the load current.
 
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