Self grounding outlet with screws only

[Kleeeniks]

Hi!

I've heard before that mounting screws are not an accepted grounding for a self grounding outlet and a grounding clip should be used, I assume the code probably says the same (I'm in NJ, USA for that matter).

I'm curious why the screws are not an acceptable ground path, is it because they are too "weak" ground conductor for high load or because they are unreliable ground conductor as they can move or something like that?

If they're considered as a too "weak" ground, then why mounting screws are an accepted self ground for light switches though?

[JoeIskor]

I didn't know that there are such screws

[Victordark]

There is not as much voltage in light switches as in conventional sockets, this is due to the fact that lamps need about 50 volts to light up, and sockets contain about 220 volts of voltage. Besides, your question is purely rhetorical, because the screws need to be used from a special grounding material so that it cannot conduct current. This metal contains the answer to your question. I personally order self-grounding screws on https://www.scrooz.com.au /, because for me there are the most high-strength and high-quality screws. However, you can also advise me your favorite hardware store, since it is not always convenient to order goods from mine.