Ground question

[LMAO]

This is probably a stupid question and as a PE I feel a little dumb for not knowing this but need to ask anyways: if an enclosure door is painted how does a ground conductor makes a conductive contact with door? Should the paint be scraped off?

 

[mwm1752]

looks factory installed -- don't touch

 

[ron]

Definitely scrape the paint. If it is factory installed, maybe by removing the lug you will see it is bare metal under there.

 

[kwired]

This is probably a stupid question and as a PE I feel a little dumb for not knowing this but need to ask anyways: if an enclosure door is painted how does a ground conductor makes a conductive contact with door? Should the paint be scraped off?

View attachment 13828

Paint may be semi conductive, but on top of that (assuming this is a stud welded to the door) you also may have a washer designed to pierce through paint along with the tightening nut compressing against the threads which will likely penetrate through any paint on those threads.

Scraping paint off doesn't hurt to give some additional assurance of a good connection though.

 

[Smart $]

You can forego scraping the paint if you place a star washer between the conductor terminal and the painted surface [250.12].

 

[cadpoint]

Article 250.96 - Bonding Other Enclosures.

Look at Article 250.110 also.