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Neutral Grounding Resistor IEC

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timm33333

Electrical
Joined
Apr 14, 2012
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198
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LY
In NEMA, the minimum voltage at which NGR (neutral grounding resistor) is allowed is 480V. What is the minimum voltage in IEC at which NGR is allowed? Thanks.
 
In my opinion you have to search this in IEC 60076-25[still in draft].
 
Sorry I meant to say that what is the general practice in IEC world: is NGR (neutral grounding resistor) used at low voltage, or is it only used at Medium Voltage?
 
From my experience in IEC world, I can say that either Low Resistance Grounding or Soild Grounding
with a coordinated ground fault protection scheme are widely used in both low & medium oltage systems.
To my knowledge there is no IEC (or even an ANSI/ IEEE standard) specifying the minimum
voltage that a NGR is allowed. The application depends on soil resistivity and other grounding practices.
In ANSI world, 25kV is the preferred volatge limit because beyond 25kV capacitance is becoming a problem during a ground fault.

 
Hi Tim,
I am pretty sure that 230V hi-resistance ngrs are used on 400/230V 3P4W systems in the iec world.
Regards,
GG


"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)

 
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