Grounding Electrode Connections: Do’s and Don’ts in NEC 2023

Understanding the Foundation: The Grounding Electrode System (GES) in NEC 2023

As professional electricians, we understand that a safe electrical installation begins from the ground up. The foundation of any robust safety system is the Grounding Electrode System (GES). Governed by NEC Article 250, Part III, the GES is a network of conductive materials in direct contact with the earth, designed to provide a path for lightning, line surges, and unintentional contact with higher-voltage lines. Its primary purpose isn’t to clear overcurrent devices but to stabilize voltage and create a low-impedance path to dissipate unwanted electrical energy safely into the earth.

Per NEC 250.52, a GES can be composed of one or more of the following electrodes, if available on site:

• Metal Underground Water Pipe
• Concrete-Encased Electrode (Ufer ground)
• Ground Ring
• Rod and Pipe Electrodes
• Plate Electrodes
• Other Listed Electrodes

Connecting to these electrodes isn’t a matter of simple attachment. The connection’s integrity is just as crucial as the electrode itself. A poor connection creates high resistance, defeating the entire purpose of the GES.

The Do’s: Permitted Methods for GEC Connections under NEC 250.70

NEC 250.70 is the definitive guide for making connections to grounding electrodes. It leaves little room for interpretation, ensuring that every connection is both mechanically and electrically sound. Let’s break down the approved methods.

Do: Use Listed and Labeled Connection Devices

The most common method for connecting a Grounding Electrode Conductor (GEC) is with a listed connector. These are typically listed pressure connectors, such as grounding clamps or lugs. The critical factor here is the “listed” designation. This means a Nationally Recognized Testing Laboratory (NRTL) like UL has tested the device for its intended purpose. For example, a clamp used on a ground rod that will be buried must be a direct-burial rated clamp. Using an indoor-only lug in a subterranean environment will lead to corrosion and a failed connection, creating a serious code violation and safety hazard.

Do: Employ Exothermic Welding for Superior Connections

When a permanent, maintenance-free, and highly reliable connection is required, exothermic welding is the gold standard. This process creates a molecular bond between the GEC and the electrode, forming a single, fused piece of metal. This is considered an irreversible connection and is superior to mechanical clamps in terms of longevity and resistance to corrosion. It is the preferred method in commercial and industrial settings and for any connections that will be made inaccessible, such as within a concrete foundation.

Do: Ensure Proper Bonding for All Electrodes

Different electrodes require specific considerations. When using a metal water pipe as an electrode, NEC 250.68(C) requires the GEC to be connected within the first 5 feet of where the pipe enters the building. Furthermore, a bonding jumper for a water pipe must be installed around any insulating sections, such as water meters or plastic fittings, to ensure the continuity of the grounding path. For a concrete-encased electrode, the connection to the rebar is often made before the concrete is poured, making it another form of irreversible connection.

The Don’ts: Common Pitfalls and Violations to Avoid

Equally important as the “do’s” are the “don’ts.” A single mistake in a grounding connection can render the entire system ineffective.

Don’t: Use Solder-Only Connections

NEC 250.70 explicitly prohibits connections that rely solely on solder. During a high-current fault condition, the heat generated can easily exceed the melting point of solder, causing the connection to fail at the most critical moment. This is a clear and dangerous violation.

Don’t: Neglect Physical Protection of the GEC

A GEC must be protected from physical damage. According to NEC 250.64(B), a GEC sized 6 AWG or larger that is not exposed to physical damage can be run exposed. However, a 6 AWG GEC that *is* exposed to physical damage must be protected in a raceway. An 8 AWG GEC, regardless of its exposure to damage, must always be protected. Proper physical protection of the GEC is a frequently cited violation that is easy to avoid.

Don’t: Improperly Splice the Grounding Electrode Conductor

Perhaps one of the most misunderstood rules in NEC Article 250 involves splicing. The general rule is that a GEC must be continuous and run without splices. However, NEC 250.64(C) GEC Splicing provides specific exceptions. Splicing is permitted only by the exothermic welding process or by irreversible compression-type connectors listed as grounding and bonding equipment.

How to Correctly Splice a GEC per NEC 250.64(C)

If you must splice a GEC, follow these steps to remain code-compliant:

1. Identify the Need: Confirm the splice is necessary for repair or extension, as a continuous run is always preferred.
2. Select the Method: Choose one of the two methods permitted by NEC 250.64(C): the exothermic welding process or an irreversible compression-type connector listed as grounding and bonding equipment. Standard split bolts or other reversible connectors are not compliant for this purpose.
3. Prepare Conductors: Clean and strip the conductors according to the specifications of the connector or welding manufacturer. A clean connection is essential for low resistance.
4. Execute the Connection: For compression connectors, use the correct die and tool to make a permanent crimp. For exothermic welding, follow all safety protocols and manufacturer instructions precisely.

Sizing and Special Considerations for Grounding and Bonding

Making a correct connection is only half the battle; the conductor itself must be sized correctly based on the size of the service entrance conductors, as detailed in Table 250.66. The code is constantly evolving, and the 2023 cycle introduced important clarifications, including changes to Grounding Electrode Conductor sizing rules that every electrician must know. Additionally, modern electrical systems often require more than basic grounding. For specialized industrial applications, understanding the updates to impedance grounding system requirements is crucial for safety and reliability.

Finally, don’t forget the Intersystem Bonding Termination (IBT) required by NEC 250.94. This device provides a dedicated point for other systems (like telephone, CATV) to connect their own grounding conductors, preventing potential differences between systems and ensuring all are referenced to the same ground.

These principles are the bedrock of a safe installation. To truly master the nuances of the updated code and earn your continuing education credits, learn more with ExpertCE’s NEC 2023 lessons.

Frequently Asked Questions about NEC 2023 Grounding and Bonding

What are the approved methods for connecting a GEC to a grounding electrode in NEC 2023?

According to NEC 250.70, the approved methods are a listed bolted pressure connector (like a clamp or lug), a listed threaded connector, exothermic welding, or a machine screw that threads into a tapped hole (minimum two threads). All connections must be permanent and effective, and any clamps used for direct burial must be listed for that purpose.

Can I splice a Grounding Electrode Conductor (GEC)?

Generally, a GEC must be installed in one continuous length. However, NEC 250.64(C) provides exceptions, permitting splices only if made by one of two methods: the exothermic welding process or with irreversible compression-type connectors listed as grounding and bonding equipment. Standard split bolts and other reversible connectors are not permitted for splicing a GEC because they do not meet the “irreversible” requirement of the code.

What is the purpose of an Intersystem Bonding Termination (IBT)?

An Intersystem Bonding Termination (IBT), required by NEC 250.94 for new buildings, is a dedicated connection point for other low-voltage systems like cable TV, satellite, and telephone. It ensures all separate systems are bonded to the same grounding electrode system, preventing dangerous potential differences and providing a safe path to ground for surges on those systems.

Why is a bonding jumper required on a metal water pipe used as an electrode?

A bonding jumper is required to maintain the electrical continuity of the water pipe electrode. Components like water meters, pressure-reducing valves, and filters are often installed after the initial electrical work and can be electrically isolated or made of non-conductive materials. The bonding jumper, installed per NEC 250.68(C)(1), bypasses these components to ensure the continuity of the grounding path, a principle also outlined in 250.53(D)(1).

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