I'm installing a new switch and outlet in a previously renovated garage, and I noticed the following:

  1. My Klein non-contact voltage tester beeps continuously on all of the metal boxes and surface-mounted MC cable.
  2. The voltage tester beeps continuously when I touch it to parts of the wood framing (rafters) and even the door hinges.
  3. All of the outlets are showing open ground using a three-light plug-in tester
  4. When I use a pin-type voltage tester to check the wiring, HOT to GROUND shows nothing, HOT to BOX/MC CABLE shows nothing. HOT to NEUTRAL shows 120V. Finally, BOX/MC CABLE to NEUTRAL shows nothing.

I've checked all of the boxes, outlets and switches in the garage, and the wiring is fine.

Any ideas for next steps?

  • 1
    Sounds like you have a wiring problem which is rendering all your grounded things hot. That's to be taken seriously, obviously, as it can kill you. Aug 25, 2017 at 18:46
  • When I lived in Ohio a house I rented was wired with the white as hot through the entire house to the panel they did not ground anything and all the fixtures and outlets were wired black to black or black to brass so everything was hot on the case you might have a similar problem.
    – Ed Beal
    Aug 25, 2017 at 18:55

1 Answer 1


Well, don't trust the no-contact tester to tell you anything but the presence of voltage somewhere close to the end of it. Beyond that they aren't much use.

From what you said in #4 you have an open ground. Also, if you used a 3 light tester and it told you you have an open ground, I would believe that.

Check your equipment ground connections for a bad splice and terminations for a loose connection. Also, if this is a garage with a sub-panel it is possible they miswired it and your ground back to the main is open somewhere.

Good luck and stay safe by working with the circuits off!

  • Thanks Archon. There's no sub-panel into the garage, just buried cable that goes somewhere :) ... eventually back to the main panel that I'll check next.
    – byron
    Aug 25, 2017 at 19:48
  • Yeah, you should check the continuity of the equipment ground from the main to the garage and see if the conductor is continuous. From there move through the circuit until you find the problem.
    – ArchonOSX
    Aug 25, 2017 at 19:55

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