Transformer Neutral Grounding Resistor Cabinet (NGR )/Electrical
Earthing Resistance Cabinet:
Diagram for Installation and Wiring AC distribution board
Neutral Grounding Resistors are used to protect power transformers,
power generators and other associated equipment in your power
systems against 50/60 Hz faults (short circuit) and transient
There are six parameters needed to specify the neutral grounding
1. Rated voltage line to neutral or system voltage.
2. Rated fault current.
3. Rated “duration time” of the line to neutral voltage not
exceeding the allowable temperature rise.
4. Rated Resistance.
5. Application environment, indoor or outdoor.
6. Enclosure material, ss plate or normal cold rolled sheet.
• Rated current: from 1 amp to 2000 A
• Rated voltage: from 6to 20 kV
• Rated Resistance: from 1 ohm to 2000 ohm
• Rated time: 1 sec to continuous time rating
TESTING AND QUALITY
with IEEE-32. Routine tests performed on each Neutral Grounding
Resistor are measurement of resistance, high voltage power
frequency, insulation measurement, aspect verification, dimensional
control. Mingrui’s internal quality system has been developed and
certified under ISO 9001 quality system
Standard unit includes the stainless steel resistor assembly plus
all the required insulators, internal connections and hardware
installed in a standard safety enclosure. Neutral Grounding
Resistor units are completely assembled, prewired, and tested at
our facility. For shipping all units are crated for added
protection and ease of handling.
• Forged eyebolts in all four corners for easy hoisting.
• Removable front and rear louvered covers for easy access for
connection and inspection.
• Corrosion resistant nameplate provides complete ratings and
•Heavy gauged enclosure polyester powder coated finish provides
•Stainless steel, cold rolled plate construction. Custom paint
finish is available.
• Top or side mounted entrance bushing(s).
• Screened covers for indoor applications.
• Support stands for elevating the enclosure above ground.
Current or potential transformers mounted and prewired at our
ON or OFF Load disconnecting switches
To serve you better, please kindly offer following information when
1 generator rated voltage, transformation ratio of grounding
transformer, resistance value;
2 insulation form of grounding transformer;
3 transformation ratio of current transformer ;
4 color of cabinet, wiring from the top or bottom;
5 time of current flowing-through
6 material and color of box, IP protective grade, colour and