Concrete Encased Electrodes
Department of Building Construction and Inspections
County of Henrico, Virginia
TO: Approved Residential Footing Inspection Agencies & Residential Building Contractors
FROM: Building Official
SUBJECT: Concrete-Encased Electrodes
DATE: April 10, 2009
Sections 3508.1 and 3508.1.2 of the 2006 International Residential Code (IRC) require the use of a concrete-encased grounding electrode whenever steel reinforcement is present in a building footing. Inspection of the concrete-encased electrode is required prior of the placement of concrete in the footing. The electrode must be at least 20 feet in length and can be of either bare copper of not less than 4 AWG or electrically conductive steel reinforcing bars of not less than 1/2″ diameter. This electrode must be encased by at least 2 inches of concrete and terminate in a location that is accessible for the electrician to attach the grounding conductor for the electrical system. Any portion of steel reinforcing bars that is not protected by at least 2 inches of concrete must be sleeved or otherwise protected to prevent corrosion and/or contact with earth. An illustration is attached to provide an example of the applicable code provisions.
The presence of footing steel will be noted on all building and electrical permits that are issued after May 1, 2009 for new single family dwellings and townhouses. Footing inspections performed for these permits must confirm the proper installation of the concrete-encased electrode. Approved Agencies that perform footing inspections for these permits shall note the installation of the concrete-encased electrode, including the location of the electrode, on the Residential Footing Inspection Report form provided by the Department of Building Construction & Inspections. Residential Footing Inspection Reports that do not confirm the installation and location of the concrete-encased electrode in steel-reinforced footings will be rejected by the Henrico County Building Inspector. Henrico County Electrical Inspectors will verify the proper connection of the grounding conductor to the electrode during the temporary service and/or rough-in electrical inspection.
Please call 501-4360 if you have any questions regarding this matter.
Gregory H. Revels, CBO