High Resistance Grounding

High resistance grounding systems (HRG) are a subset of neutral grounding resistors which allow for continuous and safer operation during ground fault conditions. Our advanced systems can detect ground faults and control transient overvoltages during phase-to-ground faults across multiple feeders, and come with many features to enhance protection, reliability, and ease of maintenance.

MegaResistors offers the best-in-class high resistance grounding on the market. Whether you’re a small production facility, a data center, or a nuclear power plant, we have systems that can meet or be tailored to your exact requirements. Scroll below to see why we are your best option for High Resistance Grounding Systems.

Seismic Rated

Seismic Rated

Seismic Rated

Seismic Rated

Seismic Rated

Seismic Rated

Advantages

Greatly enhanced safety

  • During a ground fault there is a greatly increased risk of arc flashes and transient overvoltages
  • Without adequate mitigation, this can cause death or severe injury
  • Our HRGs can prevent all of these risks from occurring, making all systems significantly safer for personnel during a ground fault

Equipment protection

  • The same events that can affect the safety of personnel, can also result in burning, melting, or catastrophic destruction of equipment
  • This can potentially cost thousands to millions of dollars in equipment replacement costs, and operational downtime
  • High resistance grounding is an investment to protect all your systems

Service continuity and faster maintenance

  • Low resistance grounding trips your system within a specified amount of time so you can shut down operations and attempt to locate and repair the ground fault source, potentially taking hours or days
  • HRGs can maintain continuous operations during a ground fault
    • With pulsing, personnel can easily locate the source of a fault
    • With our advanced systems, each individual feeder can be monitored to display exactly which feeder(s) have a fault

Advanced Feeder Protection

  • Our advanced system can protect against multiple ground faults, and assign priorities to each individual feeder
  • With additional customization, logic can be added for even more advanced prioritization
    • For example, when system priorities change as a result of other factors such as time, this can be programmed into our high resistance grounding system

Standard Models

We have three levels of standard models. Each model can be configured to your requirements, and serve as a great base for customization. If you have a completely custom requirement, you can email or call us and we’ll work with you to create a system that meets your needs.

Basic

A diagonal view of the Basic HRG in an HR1 enclosure
  • Ground Fault Protection
  • Analog Metering
  • Pulsing
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Intermediate

A diagonal view of the Intermediate HRG in an HR2 enclosure
  • Ground Fault Protection
  • Pulsing
  • Resistor Monitoring
  • Harmonic Filtering
  • Communications
  • Data Logging
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Advanced

A diagonal view of the Flagship HRG in an HR4 enclosure
  • Pulsing
  • Resistor Monitoring
  • Harmonic Filtering
  • Communications
  • Data Logging
  • Advanced Feeder Protection
  • Multi Ground Fault Protection
  • Touch Screen Interface
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Additional Resources

NGR Calculation
Learn how to calculate the necessary variables for a NGR.
Learn how to calculate the necessary variables for a NGR.
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System Capacitance to Ground Calculation
System Capacitance to Ground Calculation
Total capacitance to ground charging current of a system measuring and estimated.
Total capacitance to ground charging current of a system measuring and estimated.
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User Manual
Installation details, connections, maintenance, and more general info.
Installation details, connections, maintenance, and more general info.
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CT Ratio Modification
CT Ratio Modification
Learning how to use one CT for multiple specs. Understand ratios and turns.
Learning how to use one CT for multiple specs. Understand ratios and turns.
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Useful Information

System design implications of using resistance grounding

If you are designing a new facility or retrofitting an old one and are considering high resistance grounding, there are a few implications you must consider prior to completing the design and entering the procurement stage.

When a single phase-to-ground fault occurs, the phase-to-ground voltage on the other two unfaulted lines will increase.

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