Concrete Reference Electrode Installation Instructions

These instructions apply to EDI Model CB-AGG, a reference electrode with a gelled silver/silver chloride (Ag/AgCl) element designed for use in reinforced concrete. Be sure to follow the correct procedures. Failure to do so can significantly shorten the life of the reference electrode.
Installation in New Structures
Remove electrode from its protective packaging. Use plastic coated wire ties to secure reference electrode to the center of a rebar net square. This should be done not more than four hours before the concrete will be poured.

Installation in Existing Structures
Excavate hole to required depth for proper location. Recommended minimum dimensions for the hole are 2 ½" x 2 ½" x 8" (6 cm x 6 cm x 20 cm). A layer of the original concrete should remain between the reference electrode and the rebar. Lead wires can be embedded in saw slits. The preferred location for the reference is at the center of a rebar square at the same depth as the outer rebars. Remove electrode from its protective packaging and place it in the hole. Fill the hole with portland cement patching grout.

Caution: Do not use patching grouts containing polymer additives.

Two Wire Termination
The Model CB electrode with a two wire termination (code 2W) has a lead wire, length as specified, and a 3 foot (1 meter) structure wire. The lead wire is a shielded 2-conductor #22 AWG cable. One of the two wires in this cable is designated as "element" and is the one connected to the sensing element in the reference electrode. The other wire is designated as "structure"; this wire has been shunted within the electrode housing to the structure wire. The shield should be connected to an earth ground at the test station. The #14 HMWPE structure wire is to be attached to a rebar by brazing or cad-welding a minimum of 18 inches (1/2 meter) away from the intended location of the reference. This joint should be coated with a suitable dielectric coating. If the structure wire has the optional steel rod termination, the rod can be arc welded to a rebar and no dielectric coating is necessary.

Single Wire Termination
The Model CB electrode with a single wire termination (code SW) has a single #14HMWPE lead wire, length as specified. This wire should not share a conduit with power leads. For elevated structures, this wire should be encased in a metal conduit. These precautions will minimize errors in potential readings due to interference.