In order to ensure a good ground/bonding connection, Section 250.12 requires nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded or bonded to be removed from surfaces to ensure good electrical continuity.
Some equipment has dimpled or flared holes where a bonging screw will be installed and is not required to have the paint scraped off.
For other items, such as gas piping like in the image, paint must be scraped off to ensure a good metal to metal contact between the pipe and the bonging clamp. Paint or other nonconductive surfaces will not ensure proper continuity between the object being bonded and the bonding device.
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 NFPA 70.
2023 Code Language:
250.12 Clean Surfaces. Nonconductive coatings (such as paint, lacquer, and enamel) on equipment to be grounded or bonded shall be removed from threads and other contact surfaces to ensure electrical continuity or shall be connected by means of fittings designed to make such removal unnecessary.
Which of the following is true of a gas pipe requiring bonding?
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