Ground Generators Safely with Bender Monitoring Devices

Generator grounding plays a crucial role in maintaining the safety, reliability, and uptime of your electrical system, especially in medium-voltage and high-availability applications. At Bender, we simplify generator grounding with advanced solutions that reduce complexity while delivering unmatched performance. 

Bender recommends installing a Neutral Grounding Resistor Monitor (NGRM) on each resistor in your system. This approach reduces wiring complexity and enables dynamic control of grounding modes. 

Each NGRM can be configured to switch between: 

  • Auto Mode: Actively monitors resistance to earth.
  • Passive Monitoring Mode: Observes system conditions without influencing them.

By keeping one unit in Auto Mode at all times, you ensure continuous ground-fault monitoring, even as generators are added or removed. This setup avoids inconsistencies in resistance readings and protects your system against undetected faults. 

High-Resistance Grounding (HRG) for Generator Applications

For most generator configurations, Bender recommends using an HRG series (HRG 1, HRG 2, or HRG 3). These solutions are specifically designed to: 

  • Minimize arc flash hazards
  • Enable fault detection without tripping
  • Prevent system downtime during single ground faults

Historically, many medium-voltage generator systems have used Low-Resistance Grounding (LRG) or hybrid grounding. If converting to HRG is not feasible for your setup, Bender still offers monitoring devices and replacement parts compatible with existing LRG and hybrid systems. 

Solidly Grounded Mobile Power

North American applications for portable or mobile power generation are often solidly grounded. Bender's RCM series ground-fault relays can be used to provide ground fault protection in such applications. In other jurisdictions, mobile power generators are left ungrounded for continuity of service in applications like construction or emergency power. For applications required to meet IEC in particular, "protective isolation with insulation monitoring and shutdown," customers often use the isoGEN423. For more information on solutions for different generators, read through our downloads section below or contact us

Monitor Ground-Path Continuity
Current based ground-fault detection relies on the return path.

Enhanced Ground-Fault Protection
Non-linear loads are better protected by a relay that has wide frequency response.

Selective Coordination
Selective Coordination

Protect Generator Windings
Resistance grounding limits the amount of damage to the generator.

Looking to upgrade or design a reliable generator grounding system?

Contact Bender today to speak with an expert and find the right HRG or insulation monitoring solution for your application. 

Downloads

NameCategorySizeLanguageTimestampD-/B-Number
How to Size an NGR (US) Technical Information 424.0 KB EN2019/05/1313.05.2019
HRG & LRG Systems (US) Product Brochures 3.6 MB EN2024/01/0303.01.2024
2020 Guidelines (US) Technical Information 1.9 MB EN2020/06/1515.06.2020
Overview Brochure Product Overviews 10.3 MB EN2023/10/0202.10.2023
NGR Checklist (US) Technical Information 245.3 KB EN2022/11/0707.11.2022
Guideline on NGR/Safety Ground Monitoring Technical Information 234.7 KB EN2019/09/2020.09.2019

Products

Ground-Fault Monitoring, Ungrounded

ISOMETER® isoGEN423
ISOMETER® isoGEN423

Insulation monitoring device for unearthed AC, AC/DC and DC systems (IT systems) up to 3(N)AC, AC 400 V, DC 400 V

ISOMETER® iso685…
ISOMETER® iso685 Series

Ground-fault detector for ungrounded AC/DC systems

Resistance Grounded Systems (HRG/LRG)

LINETRAXX® NGRM500

Monitor for use in high-resistance grounded systems

LINETRAXX® NGRM700

Monitor for use in high-resistance grounded systems

Ground-Fault Monitoring for Grounded Systems

LINETRAXX® RCMA420
LINETRAXX® RCMA420

AC/DC ground-fault monitor

LINETRAXX® RCMA423

AC/DC ground-fault monitor

Ground-Fault Monitoring, Ungrounded

ISOMETER® isoGEN423
ISOMETER® isoGEN423

Insulation monitoring device for unearthed AC, AC/DC and DC systems (IT systems) up to 3(N)AC, AC 400 V, DC 400 V

Details
ISOMETER® iso685…
ISOMETER® iso685 Series

Ground-fault detector for ungrounded AC/DC systems

Details

Resistance Grounded Systems (HRG/LRG)

LINETRAXX® NGRM500

Monitor for use in high-resistance grounded systems

Details
LINETRAXX® NGRM700

Monitor for use in high-resistance grounded systems

Details

Ground-Fault Monitoring for Grounded Systems

LINETRAXX® RCMA420
LINETRAXX® RCMA420

AC/DC ground-fault monitor

Details
LINETRAXX® RCMA423

AC/DC ground-fault monitor

Details

Standards

CSA C22.2 No. 295
IEEE C57.32
IEEE 3003.1
UL 508
CSA C22.2 No. 14
NFPA 70

National Electrical Code

CSA C22.1

Canadian Electrical Code