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Neutral Grounding Resistor IEC

Neutral Grounding Resistor IEC

Neutral Grounding Resistor IEC

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.

RE: Neutral Grounding Resistor IEC

In my opinion you have to search this in IEC 60076-25[still in draft].

RE: Neutral Grounding Resistor IEC

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?

RE: Neutral Grounding Resistor IEC

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.

RE: Neutral Grounding Resistor IEC

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

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