Is the nonconductive coating "ALWAYS" required to be removed for bonding and grounding electrical equipment?

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Willie Snyder

Willie Snyder

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Electrical Foreman / Certified NICET II Fire alarm technician
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Non-conductive coatings are not required to be removed to bond electrical equipment because modern bonding methods and materials can effectively penetrate these coatings to establish a reliable electrical connection. These coatings, often applied for protection against corrosion or environmental damage, do not significantly impede the bonding process due to the following reasons:

  1. Penetrative Bonding Techniques: Many bonding methods, such as the use of self-piercing fasteners or specialized conductive adhesives, can penetrate non-conductive coatings, ensuring a good electrical contact without the need to remove the coating.
  2. Enhanced Conductive Materials: Some bonding systems incorporate materials with enhanced conductive properties that can establish an electrical connection through thin non-conductive layers.
  3. Regulatory Acceptance: Electrical codes and standards have evolved to recognize the effectiveness of modern bonding techniques that do not require the removal of non-conductive coatings, provided they meet specific performance criteria.
Overall, these advancements streamline the bonding process, save time, and preserve the protective benefits of the coatings while ensuring electrical safety and reliability.
 
Factory connected bonding and grounding equipment does not require anything to be removed if the equipment tested and listed with the coating in place. That would apply to the neutral/EGC bar in the photo.
 
electrofelon said:
Bill, I'm not entirely sure I follow. Is there a question? Is the body of the original post from you or from another source? If another source, are you questioning that source?
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I am saying 250.12 applies to raceway and cable bonding and the nonconductive paint is not required to be removed as long as 250.8(A)(6) is complied with I just always heard that reference tossed out there and never realized the word fitting meant cables and raceway bonding.
 
infinity said:
Factory connected bonding and grounding equipment does not require anything to be removed if the equipment tested and listed with the coating in place. That would apply to the neutral/EGC bar in the photo.
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I would take it a step further and say 250.12 doesn't apply
 
Bill Snyder said:
I am saying 250.12 applies to raceway and cable bonding and the nonconductive paint is not required to be removed as long as 250.8(A)(6) is complied with I just always heard that reference tossed out there and never realized the word fitting meant cables and raceway bonding.
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Standard locknuts when tightened properly will ensure that the connection is suitable to ground the raceway and vice versa without having to remove the paint.
 
My thought has always been that if something like the EGC bar like shown in OP is mounted to a hole(s) that is provided by the manufacturer for that purpose then it is listed for installation that way without needing to remove paint or other coatings.

If you mounted it in your own custom location you very well may need to remove paint or other coatings to assure continuity, or at least possibly provide a separate bonding jumper to assure continuity.
 
kwired said:
My thought has always been that if something like the EGC bar like shown in OP is mounted to a hole(s) that is provided by the manufacturer for that purpose then it is listed for installation that way without needing to remove paint or other coatings.

If you mounted it in your own custom location you very well may need to remove paint or other coatings to assure continuity, or at least possibly provide a separate bonding jumper to assure continuity.
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I agree. In factory installed equipment it could be connected with bubble gum if it's tested and listed.
 
infinity said:
Standard locknuts when tightened properly will ensure that the connection is suitable to ground the raceway and vice versa without having to remove the paint.
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I also agree with that statement.

If reducing washers are used however they typically have no method to assure bonding has occurred when there is paint or other possible insulating covering involved.
 
The equipment/terminations as delivered from Manufacturers has been tested in the factory with a NRTL and are certified as compliant.

In the field it is treated somewhat differently. If the means being used to bond to the enclosure is listed or labeled or identified as suitable, then removing the surface coating is not required. Not all of the 250.8 means are suitable without removing the paint.

250.8(5)+(6) - the screws require either 24 or 32 threads/inch to catch 2 threads. Not all enclosures are of the same thickness. I spent quite a bit of time with manufacturers of the enclosures/back boxes and the screws, to come to the conclusion of 24/32 threads/inch. I did reach out to other industry people before the manufacturers.

My personal preference is not to depend on 2 threads at any service location. The amount of energy that is available at the service location is too high for the facilitating of opening and OCPD is too critical. Remember, I said, my opinion. And, removing the paint is not difficult if one carries metal sanding paper and even steel wool.
 
PCBelarge said:
250.8(5)+(6) - the screws require either 24 or 32 threads/inch to catch 2 threads. Not all enclosures are of the same thickness. I spent quite a bit of time with manufacturers of the enclosures/back boxes and the screws, to come to the conclusion of 24/32 threads/inch. I did reach out to other industry people before the manufacturers.
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If you have 1/16" thick enclosure and have a screw used for bonding tapped into enclosure then you must use 32 thread per inch screw to get 2 threads engaged. A raised bump intended for a bonding screw however will typically have more thickness at that point.
 
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