Code Change Summary: Revised code language provides clarity on water piping considered within 5 feet of the point of entrance to the building.
For years, it has been acceptable to connect a bonding wire to interior metal water piping that is joined to the underground metal water piping serving as the grounding electrode as long as the bonding connection is located within 5 feet of where the water piping enters the building.
Having this connection within the first 5 feet of the point of entry of the water piping helps to ensure that the bonding to the grounding electrode will remain intact even through future remodels or construction that may alter the interior water piping configuration.
Future plumbing work or replacing portions of the interior metal water piping is less likely to disrupt the bonding of the electrical system to the metal underground water pipe electrode when the bonding connection is made as close as possible to where the water piping stubs up out of the ground and enters the building.
In the 2023 NEC® a public input was accepted which will ensure the intent of Section 250.68(C) is clear. In the 2023 NEC®, it is still permitted to use the interior metal water piping to extend the bonding connection from the service to the metal underground water piping that qualifies as a grounding electrode, but the bonding connection must be made within 5 feet of where the piping enters the building, “as measured along the water piping”.
A good plumber will be efficient with the use of interior copper water piping and configure the piping to use as little as possible. This often results in stubbing up the metal underground piping in a location where immediate termination to plumbing appliances can occur.
Stubbing up the metal underground water piping into a crawl space or basement in close proximity to the water heater and well pressure tank makes it easy to use as little copper as possible to supply the plumbing equipment and to distribute the water supply piping to the rest of the building. This method also results in more than 5 feet of interior metal water piping (measured along the piping) that are all within 5 feet horizontally (as the crow flies) of where the underground metal water pipe enters the building (see image).
The revised language in Section 250.68(C) helps to avoid situations where the underground metal water piping enters the building into a basement or crawl space and connects to interior metal water piping that is technically within 5 feet of the point of entry but is actually located more than 5 feet (as measured along the piping).
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC® edition of NFPA 70.
2020 Code Language:
250.68(C) Grounding Electrode Conductor Connections. Grounding electrode conductors and bonding jumpers shall be permitted to be connected at the following locations and used to extend the connection to an electrode(s):
(1) Interior metal water piping that is electrically continuous with a metal underground water pipe electrode and is located not more than 5 feet from the point of entrance to the building shall be permitted to extend the connection to an electrode(s). Interior metal water piping located more than 5 feet from the point of entrance to the building shall not be used as a conductor to interconnect electrodes of the grounding electrode system.
2023 Code Language:
250.68(C) Grounding Electrode Conductor Connections. Grounding electrode conductors and bonding jumpers shall be permitted to be connected at the following locations and used to extend the connection to an electrode(s):
(1) Interior metal water piping that is electrically continuous with a metal underground water pipe electrode and is located not more than 5 feet from the point of entrance to the building, as measured along the water piping, shall be permitted to extend the connection to an electrode(s). Interior metal water piping located more than 5 feet from the point of entrance to the building, as measured along the water piping, shall not be used as a conductor to interconnect electrodes of the grounding electrode system.
According to 2023 NEC Section 250.68(C), when bonding to interior metal water piping that is connected to an underground metal water pipe grounding electrode, which of the following is true?
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