Background

The Ufer ground is a grounding system that utilizes the concrete encased reinforcing steel of a building to provide a low-resistance path to the earth. The Ufer ground wire is connected to the rebar in the concrete and then to the electrical system of the building.

Your Situation

You have terminated the Ufer ground wire to the ground bonding screw in the transformer. However, the city inspector is asking you to intercept the Ufer ground wire to either the service or building panels using an exothermic procedure.

Exothermic Procedure

An exothermic procedure is a type of electrical connection that uses a chemical reaction to produce heat. This heat melts the metal conductors together, creating a permanent bond.

Inspector's Request

The inspector's request is probably based on local code requirements that may vary from municipality to municipality. In some areas, it may be considered best practice to have the Ufer ground wire intercepted to the service panel to ensure a direct and low-resistance path to the earth.

Advice

It is advisable to comply with the inspector's request and intercept the Ufer ground wire to either the service or building panels using an exothermic procedure. This will ensure that the electrical system meets local code requirements and provides a reliable ground path for your building.

Procedure:1. Identify the location where the Ufer ground wire will be intercepted.
2. Cut the Ufer ground wire and remove a small section of insulation from each end.3. Clean the conductor surfaces thoroughly.
4. Apply exothermic welding compound to the conductor surfaces.5. Insert the conductors into the exothermic mold and activate the reaction.
6. Allow the connection to cool and inspect it for proper bonding.7. Connect the intercepted Ufer ground wire to the service or building panel as required by the inspector. Flag for review