Okay, let's break down the NEC 2023 requirements and apply them to your situation. I will need a little more information.

NEC 2023 and Metal Water Piping Systems

The National Electrical Code (NEC) generally requires the bonding of metal water piping systems to the grounding electrode system. The purpose is to create a low-impedance path for fault current to return to the source, allowing overcurrent devices (breakers or fuses) to trip and clear the fault. This reduces the risk of electric shock and fire.

Key NEC Sections to Consider (NEC 2023)



250.50 Grounding Electrode System. This section outlines the requirements for a grounding electrode system, which includes things like grounding rods, concrete-encased electrodes (ufer grounds), and metal water pipes. 250.52(A)(1) Metal Underground Water Pipe. "A metal underground water pipe that is in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulated joints or insulated pipe) to the points of connection of the grounding electrode conductor and the bonding conductors shall be considered as a grounding electrode." 250.104 Bonding of Piping Systems and Exposed Structural Metal. This is a crucial section. It specifies where and how metal water piping systems must be bonded. (A) Metal Water Piping. "The metal water piping system shall be bonded as required in (A)(1), (A)(2), or (A)(3) of this section." (1) General. "Metal water piping system(s) that are interior to a building or structure shall be bonded to any of the following:" (Lists several acceptable points, including the service equipment enclosure, grounded conductor at the service, the grounding electrode conductor, etc.) (2) Multiple Buildings or Structures. (Deals with bonding requirements in multiple buildings - likely not relevant to you). (3) High Impedance Grounded Neutral System. (Not typical in residential applications). 250.68 Connection to Grounding Electrode. This covers how to make the physical connection to the grounding electrode.

Analyzing Your Situation (Based on Your Description)


Metal Water Pipe Length

The crucial factor is

how much of the metal pipe is underground and in direct contact with the earth for at least 10 feet (3 meters). This is the determining factor of whether it is considered a grounding electrode. If the metal section is less than 10 feet buried in the ground, then 250.104(A) applies. If the metal section is more than 10 feet buried in the ground, then 250.52(A)(1) applies.
2. Electrical Continuity

Even if you have 10+ feet of buried metal pipe, you have to ensure it's electrically continuous. The key questions are: Is the metal section continuous? Are there any insulated couplings within that 10+ foot section?

Possible Scenarios and Requirements



Scenario 1: Metal Section is <10 Feet Buried

If the metal pipe is less than 10 feet buried in the ground, then NEC 250.104(A) applies. The metal pipe must be bonded.

Scenario 2: Metal Section is >=10 Feet Buried and Electrically Continuous

If the metal pipe is 10 feet or more in direct contact with the earth and electrically continuous, it's considered a grounding electrode (250.52(A)(1)). It is a grounding electrode and must be connected to the grounding electrode system. The bonding connection is a critical part of the grounding system.

Scenario 3: Metal Section is >=10 Feet Buried but NOT Electrically Continuous

If the metal pipe is 10 feet or more in direct contact with the earth but is not electrically continuous due to insulated couplings, you cannot rely on it as a grounding electrode. If you were to bond to this pipe, it needs to be made electrically continuous.

How to Determine Compliance


Determine Metal Pipe Length

Accurately measure the length of the metal water pipe that is buried in the ground.2.

Check for Electrical Continuity

Use a multimeter to test for continuity across the metal pipe. There should be a very low resistance reading (close to zero ohms) between different points on the pipe.3.

Inspect for Insulated Couplings

Visually inspect the buried section (as much as you can) for insulated couplings or fittings that would break electrical continuity.

My Recommendation

Given the general requirements of the NEC and the potential hazards associated with ungrounded metal water pipes,

it's generally a good practice to bond the metal water pipe, regardless of the exact buried length, especially in a residential setting. The contractor did the right thing The cost of bonding is relatively low compared to the potential risk of an electrical fault causing a shock hazard.

Important Considerations



Grounding Electrode Conductor (GEC) Size

The size of the GEC connecting the metal water pipe to the grounding electrode system must be sized according to NEC Table 250.66. This table is based on the size of the service entrance conductors.

Bonding Jumper Around Water Meter

If there's a water meter, you need to ensure that there's a bonding jumper installed around the meter to maintain electrical continuity.

Local Codes

Always check with your local electrical inspector for any local amendments or interpretations of the NEC. Local jurisdictions can have stricter requirements.

Disclaimer

I am an AI chatbot and cannot provide definitive electrical code interpretations. This information is for general guidance only.

Consult with a qualified and licensed electrician in your area for specific advice on your situation. They can properly assess your wiring, local codes, and ensure your electrical system is safe and code-compliant. Flag for review