IMPORTANT: Read and understand all instructions, cautions, and warnings in the owner’s manual before operating the generator. Do not modify the generator’s wiring, grounding connections, or neutral configuration. If any instructions are unclear, contact Generac Customer Support or an Independent Authorized Service Dealer (IASD).

Does a portable generator need to be grounded?

Grounding requirements for a portable generator depend on the type of generator, how it will be used, the connected equipment, and local electrical codes. Review the information below and follow all requirements that apply to the specific generator and application.

Environment

This article applies to Generac portable generators used to power cord-and-plug connected equipment or connected to an approved building electrical system.

How to determine the grounding requirements

Grounding requirements are specific to the generator and its intended use. Review all applicable resources before operating or connecting the generator:

• Review the owner’s manual for the specific portable generator model
• Check applicable federal, state, and local electrical codes or contact the local Authority Having Jurisdiction (AHJ)
• Review the installation manuals for any transfer switch, power inlet box, connecting cord, or other connected equipment
• Contact a licensed electrician when the requirements are unclear or electrical installation work is required

Enter the generator’s model or serial number on the product lookup page to find available owner’s manuals and other product documentation.

Note: Grounding instructions for one portable generator model or application may not apply to another.

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?
• Generac does 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 the 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. Consult the local AHJ to ensure that all relevant regulations are met.

When to contact a professional

Contact the local AHJ or a licensed electrician when:

• Local grounding or electrical requirements are unclear
• The generator will be connected to a home, building electrical system, transfer switch, or main load center
• A ground rod or other grounding equipment may be required
• The installation may require an electrical modification

Contact Generac Customer Support or an Independent Authorized Service Dealer when the generator’s manual, neutral configuration, or compatibility information cannot be confirmed.

Use the dealer locator to find an Independent Authorized Service Dealer.

See also

• Where can I download a user manual for my Generac portable generator?
• Does my portable generator have a bonded or floating neutral?
• What is a manual transfer switch?
• What is the HomeLink manual transfer switch?