1

I used an existing Romex cable that was not connected to anything (it has power bc I tested with a non contact tester). I drilled through my plaster wall and fed the cable to the outside.

I added an external junction box so that I can install my flood light / camera.

I connected the hot, neutral, ground to my light/camera but did not ground the box.

I didn’t connect the ground bc I wasn’t sure if the ground in the Romex connected to ground.

(1) should I connect the romex ground to the box and pigtail to the light?

(2) how do I tell if the ground wire is properly grounded?

Improve this question
7
  • If it was not connected to anything, as you state, it would have no power and no ground. So if there's power, it was connected somewhere, and should be (but you should find it & check) connected to ground there.
    – Ecnerwal
    Commented Apr 21 at 19:16
  • I tested with a non contact tester and it has power. I connected the light and camera and it’s working. It’s hard to trace the cable bc it’s in the ceiling
    – milesmeow
    Commented Apr 21 at 19:22
  • 2
    Is the box metal or plastic? Metal boxes should be grounded/connected to ground, Plastic is useless. A multi-meter will show 120v between hot and ground, if ground is good/connected to the panel.
    – crip659
    Commented Apr 21 at 19:30
  • 2
    If for some weird reason/mistake/some idiot it is not connected, then connecting will be exactly the same as not connecting. It will give a wrong sense of safety, but for the circuit working or not, it does not matter. Ground is there to pass shorts to the panel and trip the breaker, preventing fires and only giving a shock instead of killing.
    – crip659
    Commented Apr 21 at 21:27
  • 1
    With a dmm, if the ground is connected, hot to ground should show 120v (+/-). Neutral to ground should show 0v and continuity.
    – Aloysius Defenestrate
    Commented Apr 21 at 21:45

3 Answers 3

Reset to default
3

Yes, ground the junction box. Connect the Romex ground to the box and pigtail it to the light/camera. Use a multimeter to ensure 120V between hot and ground, and 0V between neutral and ground.

Improve this answer
0

Many ways to determine if ground is connected, but given the lack of history on the line, I would want to make sure black is hot and white neutral as well. You would do well to invest in a plug-in wiring "analyzer" that tests whether hot, neutral, and ground are correctly wired. Start by shutting off the power (confirm with your non-contact tester), so you can temporarily attach a grounded outlet (black to gold, white to silver, green/bare to ground). Plug in the new tester before turning power on, and the tester should tell you whether the wiring is correct and complete.

Improve this answer
3
  • There’s no receptacle. I’m just testing the stripped wire leads. I was able to use a multimeter as suggested in the comments to the original post.
    – milesmeow
    Commented Apr 21 at 22:53
  • Understood. Outlet only temporary so you can plug in the analyzer. I recommended it in your situation because there are ways a DMM can mislead and mask a dangerous condition. (E.g., It has a high input impedance for voltage measurement, which can make a resistive circuit appear to be conductive; and you have to interpret the resistance readings in light of the circuit, i.e., how close to zero must it be to qualify as a connection. These can be problematic if the user doesn’t understand their implications.
    – MadMonty
    Commented Apr 24 at 3:17
  • I would trust a meter more than the typical $10 outlet tester. Even if it's a $5 meter.
    – keshlam
    Commented May 22 at 14:33
-1

I took Aloysius' advice and used a multimeter to see if ground was connected properly. I tested voltage difference between hot and neutral (got 120). I tested voltage difference between hot and ground (also got 120). I tested the continuity of neutral and ground...and they were connected.

This gave me confidence to ground the junction box.

So, I installed a pigtail on a junction box and connected that to the Romex neutral and the light's white wire.

Improve this answer
1
  • 8
    Wait - you connected the box to the white wire? Turn off your circuit immediately. Bare copper is ground. White is neutral and normally carries current.
    – Sort of Damocles
    Commented Apr 22 at 10:37

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