grounding w/painted fixture box

Hello -- Two questions about grounding a standard 4-foot fluorescent fixture, fed from conduit. The fixture is grounded with a grounding screw and pig tail connected to the circuit ground wire. I expect that the conduit is supposed to be grounded via its physical connection to the fixture. However the fixture is painted, and doesn't make a good electrical connection with the conduit fittings. I can scrape a bit of paint off around the knock-outs to improve the connection. Is that what is usually done?
Also, I note that the fixture is actually composed of five separate pieces of stamped sheet metal, which were painted prior to assembly. They don't actually make good electrical connection with each other. In particular, there's no continuity between the sheet with the grounding screw and the panel with the knock-out where the conduit connects. This seems really odd. If there isn't continuity between the different sheets, I'm not sure how the grounding is supposed to work. Connecting them electrically would probably mean completely disassembling the unit and sanding or scraping off the paint where the different parts connect. Do people actually do this?
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I think you're getting carried away. Scuff the paint from the fixture where the lock nut connects or buy a grounding bushing for that size conduit and attach a wire from it to the fixture body

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snipped-for-privacy@gmail.com wrote:

Probably what is usually done is nothing... You can get conduit bushings with ground screws however I think you would still need to scrape paint if that end part with the knock outs really did not get grounded some other way.

Did you have the fixture fully assembled when you measured the continuity? My cheap <$10 made in China fixtures have screws on each end that appear to tie all the metal parts together. If you remove the screws during installation or changing a ballast etc., then maybe some of the metal parts are not connected while the unit is partially disassembled. The ballast however would be grounded all the time as the ground screw is on the same metal part.
Is the fixture UL certified?
Kevin
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