Rebar as Grounding Electrode: Research Summary

Introduction

The use of steel rebar as a grounding electrode in electrical systems is a practice supported by various regulatory bodies and industry standards. This document provides a summary of findings from various sources on this topic.

Key Findings

• Rebar is commonly used in concrete construction for its superior resistance to corrosion and strength. It can also serve as a grounding electrode when embedded in a concrete slab.
• Concrete-encased electrodes, often known as "Ufer grounds," are effective due to concrete's better electrical conductivity compared to soil.
• Regulations such as the National Electrical Code (NEC) in the U.S. and BS 7671 in the U.K. acknowledge the use of rebar as a grounding electrode and provide guidelines for its installation and testing.
• According to the NFPA, there are 8 items that can form the grounding electrode system, one of which is concrete-encased electrodes like rebar. These items are interconnected to form the grounding electrode system, providing a low-impedance electrical path to the earth.

Sources

1. NEC requirements for grounding and bonding rebar
2. Guide to Concrete Rebar
3. Basic Knowledge Earthing
4. Earthing Modelling of Concrete Slabs
5. Is Rebar Grounded Or A Grounding Rod?
6. Rebar Earthing Solutions
7. Using Rebar as Earthing
8. Grounding/Earthing Via Rebar - Any Comments?
9. Understanding Our Electrical World: 8 Items that Form the Grounding Electrode System