Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns.  

Does a portable generator need to be grounded?

For safety reasons, it is crucial to understand whether a portable generator needs to be grounded when in use. Ultimately, local code will dictate whether generator grounding is required in your scenario. Check with your Authority Having Jurisdiction (AHJ) to learn about local codes in your area.

Additional factors that influence external grounding decisions include:

• The type of portable generator (open frame or portable)
• The generator's intended use (Job site, RV camping, connecting to building electrical system, etc.)
•  Whether the portable generator incorporates a bonded or floating neutral: What does it mean for a generator to have a bonded or floating neutral?
  

Environment

This article applies to Generac portable generators. Always reference the owner's manual for your specific generator model for the most accurate information about grounding.

 

Portable generator grounding considerations

Follow local codes

Ultimately, local code will dictate whether generator grounding is required in your scenario. Always check with your Authority Having Jurisdiction (AHJ) to learn about local codes in your area.

Owner’s manual is the primary source

The source of truth for all grounding questions is the owner's manual for your portable generator model. Where can I download a user manual for my Generac portable generator?

Grounding requirements

The need to ground a portable generator depends on the type of generator and its intended use:

• If a generator is supplying power to cord-and-plug connected equipment (such as power tools), grounding with a ground rod is generally not necessary.
• When connecting the portable generator to a building electrical system, manual transfer switch (MTS), or main load center, only one neutral-to-ground bond is permitted in the entire system. This bond typically exists in the main service panel or the manual transfer switch.
• If connecting an open frame portable generator with a bonded neutral to a building electrical system that includes a neutral-to-ground bond, externally grounding the generator with an earth ground rod is not necessary.
• Generac HomeLink manual transfer switches meet this requirement and are recommended for use with portable generators: What is the HomeLink manual transfer switch?
  
• We do not recommend connecting inverter style generators with a floating neutral to a building electrical system.

Neutral-to-ground bonding rules

• The NEC requires that the neutral must be grounded at the first means of disconnect (the nearest possible point) and cannot be grounded twice.
• Multiple bonds can cause induced transient voltages or currents, creating hazards.
• Adding an additional bond at the generator or elsewhere can create a dangerous condition known as a "double bond," which can lead to electrical hazards and equipment damage.

Earth ground rod considerations

• Most Generac portable generators do not require or recommend the use of an earth ground rod. In fact, adding an earth ground rod can increase the risk of damage from lightning strikes, even indirect ones conducted through the ground.
• However, local codes may require an earth ground in some jurisdictions. Always follow the requirements of your local AHJ.
• If local code mandates an earth ground, the rod should be driven at least 8 ft into the earth and securely connected to the generator's ground lug using an appropriate ground cable.

Compliance reminder

Adhering to all applicable federal, state, and local codes and regulations regarding grounding is required. Please consult your local AHJ to ensure that all relevant regulations are met.