What Are the Requirements for Mounting A Home Standby Generator to Concrete?

This article provides concrete pad installation and anchoring guidance for air-cooled home standby generators, including Next Generation (NXG) and Guardian Series models. It outlines recommended slab dimensions, leveling requirements, and anchoring practices to ensure proper installation. The guidance includes generator footprint measurements, bolt size recommendations, mounting hole locations, and code compliance considerations. Installers are advised to use the integrated composite pad, follow applicable federal, state, and local codes, and use the carton template to accurately mark and pre-drill mounting holes when securing the unit to a concrete base.

  • May 7, 2026
  • Knowledge

Title
What Are the Requirements for Mounting A Home Standby Generator to Concrete?
URL Name
What-Are-the-Requirements-for-Mounting-A-Home-Standby-Generator-to-Concrete

Public Answer

Environment

This article applies to air-cooled home standby generators.

Concrete mounting and installation guidance

To install your generator on a concrete slab:

  • Prepare a rectangular area that is approximately 5 inches thick (A), and 3 inches longer and 3 inches wider (B) than the footprint of the generator on all sides. See generator dimensions below.
  • The generator must be level within .5inches (13mm)

Generator dimensions

NXG footprint:
  • 46.4″ L × 26.3″ W
Guardian footprint:
  • 48″ L × 25″ W

If local code requires anchoring, the distance to which the bolts are sunk into the concrete is determined by the local inspector. Otherwise, the installer should ensure the unit is properly anchored per applicable codes and site conditions.

Example of home standby generator mounting hole locations inside enclosure.

Mounting hole locations for anchoring

For Next Generation Series generators, the four pallet bolt locations are used to mount generator to concrete base. See Figure 2-2 below.

  • Do not remove integrated composite pad for mounting generator to concrete. The integrated composite pad is pre-drilled to accommodate mounting bolts. 
  • Four mounting holes are available if codes require securing generator to concrete. Mounting holes are located inside the generator compartment—one near each corner.
  • Four 3/8 in (or M10) lag bolts (not supplied) are recommended for securing generator to a concrete pad. 
  • Follow all federal, state, and local codes that may be in place regarding mounting the generator on the slab.

Note: The top of the generator carton has a template which can be used to mark concrete pad to pre-drill the mounting holes. 

For Guardian Series generators, there are three mounting holes located inside the generator compartment: two in front and one in back.

  • Do not remove integrated composite pad for mounting generator to concrete. The integrated composite pad is pre-drilled to accommodate mounting bolts. 
  • Three 3/8" (or M10) lag bolts (not supplied) are recommended for securing the generator to a concrete pad.
  • Follow all federal, state, and local codes that may be in place regarding mounting the generator on the slab.

Note: The top of the generator carton has a template which can be used to mark concrete pad to pre-drill the mounting holes.

 

See also

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