0

When using metallic conduit as the ground wire, how do you confirm that the conduit provides a solid end-to-end connection?

If using an ohm meter, how would you set it up and how many ohms are acceptable?

Do inspectors check these things somehow?

1 Answer 1

4

Install it properly with clean metal-metal contact.

  • Don't just hand-spin the conduit nuts, get a screwdriver and hammer and tighten them by putting the screwdriver on the serrations made for that purpose and tapping.

  • On the conduit compression fittings, tighten those with a wrench.

  • On setscrew fittings, tighten the setscrews with a tool.

Since metallic conduit has massively more conductivity than any size of ground wire appropriate for any circuit that will fit inside it, I don't think an ohmmeter measurement would be constructive.

3
  • Good point on spinning the conduit nut with screwdriver+hammer. I didn't realize thats what the nut edges were for!
    – KJ7LNW
    Sep 17, 2021 at 20:41
  • I asked a similar question adding that the EMT is connected to a painted box. My interpretation of the answers was that doing that reliably requires some skill, training and experience and needs to be done purposefully.
    – jay613
    Sep 17, 2021 at 20:48
  • I run a seperate ground wire, I have seen many times where over time the condulet becomes separated and or the joints oxidize and the resistance goes up. This can become a problem with electronic controls.
    – Gil
    Sep 17, 2021 at 21:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.