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I wired 8 recessed lights to a switch in a room. When I connected everything the first time and turned on the power, the breaker tripped. If I disconnect the ground that leads to the breaker box on this line, it doesn't trip the breaker, the lights turn on, but I get odd readings.

Using a digital multimeter and touching the black lead to the exterior of the recessed lights and the red lead to my finger, the multimeter reads 18 volts, so basically the ground is carrying voltage to the can lights. If I test the ground and the neutral mid-line (at a junction box between two of the lights), I am getting 50 volts. Neutral to hot reads 120 volts, and hot to ground reads 66 volts at the same junction box. Any thoughts?

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    You are not a good ground. Reading voltage between your finger and the grounding conductor means nothing. – Tester101 Sep 28 '14 at 23:04
  • I understand, but what would lead to any voltage being present? If I touch one lead to the exterior of the light and one lead to a piece of exposed ductwork, it reads 50 volts. My thought is that it should be close to zero. – user25599 Sep 28 '14 at 23:18
  • Could be an open ground, where the grounding conductor isn't connected all the way back to the panel? If the breaker is tripping, there's likely a short to ground. Disconnecting the grounding conductor means there's no path for current to flow, so the breaker no longer trips. – Tester101 Sep 28 '14 at 23:24
  • Short to ground was my initial thought, so I have started going through each junction box and light fixture looking for any place a hot is contacting a ground. No luck yet, but thanks for the help. – user25599 Sep 29 '14 at 0:20
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    You should probably disconnect everything and start over. You may not have gotten the wire nuts connected well enough. – Brad Gilbert Sep 30 '14 at 0:14
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I just had a similar problem. Is the voltage in your outlets fluctuating? Mine was and the problem was out at the pole. A tree branch pushed the neutral wire at the pole against the ground wire. I kept getting around the same voltage in my ground wire.

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You have an open neutral. Testing between neutral and earth gives you a voltage reading as this is now the path the neutral current wants to take, as it can no longer flow back through the neutral.

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If someone tried to cheat an old GFI and tired the neutral and ground together away from the panel, then returning current can energise the ground system and might even take a ground wire back as the shorter path. Also if someone made a neutral ground reverse the ground system takes back the returning current and anything bare gets heated up, I think some kid got killed in a ground neutral reverse in Australia on some 230V when he turned on the hose and got between two grounds.

Bonding everything (across water meters, water softener pipes, hot water heater pipes, run a bond to the gas line and at the furnace) works to equalize the ground, you get hit when there's a difference. Also the white wire is your first to make and last to break, if you get hit, the neutral takes current back and you might only get some of it when you get hit to the ground , (where the neutrals and grounds meet at the main panel only) if there's current and you get between the hot and the ground, or between two neutral wired taking current back to the panel, you become the path and it is much worse than just getting shocked off of the hot wire while the connected neutrals are taking back most of the returning current, you can get hit harder off the whites as you can share a neutral between two circuits on different phases, and if there's no lights or anything taking up current as a load, you get it all, 220. 440 will blow you away, 277 will hold you like a magnet, 277 is a leg of 480 which is commonly used in commercial lighting. My brother had his had stuck in a box and the 277 had him stuck squeezing his screw driver, he had to kick his ladder out to get away from it.

Also if you have to hang a light with unidentified wires, use a continuity tester to the hot in the socket to keep your wires straight, you don't want the large threaded sleeve of a light bulb socket to be wired to the hot or if the bulb is out and the switch is in you can get shocked easily to ground, it's much harder to stick your finger all the way in and hit the hot tab (old illegal California 3 ways create this problem since switching reverses the hot and neutral wires instead of using dedicated travelers). Old cloth wiring can be deceitful and needs to be tested, sometimes the white wire cloth is dirty and looks black, people get hots and neutrals reversed sometimes because the white cloth wire is dirtier than the faded black one. If you suspect s ground neutral bonding anywhere other than the main panel itself, or a neutral ground reverse, you can use amp clamps around the metal gas and water lines to see if there's current (.2a is what they say can be lethal, and it can be hard to determine how much the system is actually taking since the water will absorb the current and act as a load. If there is an amperage reading with the clamps around water pipes and gas pipes it could be from a neutral ground reverse (found one where on a pull chain light with an outlet they had it miswired on the outlet plugin) or the current reading with the amp clamps around the pipes could be coming from a voltage leak, say from buried underground electric, feeding the house or bad underground wiring feeding say a yard light. Also the neutrals never are on the same bar as the ground wires in a sub panel, they must sit on a floating neutral bar, if using a regular panel tub as a sub panel you must remove the ground bonding screw from the neutral bar.so the metal panel and grounds are not touching the whites anywhere but back at the main panel.

Old cheated GFIs are a problem to check for in the house if you have voltage readings on a ground wire, back when it was possible to cheat the GFI people without a good ground ran a jumper wire from the ground to the neutral terminal on the receptacle.

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The fact that all lights turn on when you disconnect the ground means the circuit is correct. When it trips on connecting the ground means there is short circuit in the breaker box to hot. there could be some metal burr which you would not have noticed. check the box thoroughly.

  • The short could be anywhere in the circuit. When the grounding conductor is connected, the electricity has a path to flow along which causes the breaker to trip. – Tester101 Oct 1 '14 at 11:03
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I wired 8 recessed lights to a switch in a room. When I connected everything the first time and turned on the power, the breaker tripped.

  • The breaker tripping upon initial power up shows that you had the power and ground wires touching somewhere in your newly installed wiring. The problem is not in the electrical panel if the switch was existing. The problem is between the switch and the last can light. Now, with the ground disconnected if the lights work but you get weird readings... its because of the hot to ground problem.

hot to ground reads 66 volts

  • either you only have 66 volts on the hot.... or you have a bad (not well connected) ground. its possible that when the breaker tripped, the short caused burning between the black and ground. imagine a welder striking an arch. it leaves slag which, like an electric stove, resists the flow of voltage, reducing it to less than optimum (120 ish)

Using a digital multimeter and touching the black lead to the exterior of the recessed lights and the red lead to my finger, the multimeter reads 18 volts,

  • You should not be doing electrical work. you are a hazard to yourself.

so basically the ground is carrying voltage to the can lights.

  • No, you have energized the metal housing of the can with the black wire. Now, touching them could kill you.

If I test the ground and the neutral mid-line (at a junction box between two of the lights), I am getting 50 volts.

  • this is because the ground is energized. but it could also be that voltage going through a light and trying to return to the electrical panel on the white, but not being able to get there due to an open neutral that is touching the bare metal of the can light or a ground wire. The housing is still energized and ready to kill someone.

Neutral to hot reads 120 volts,

  • as it should.

and hot to ground reads 66 volts at the same junction box.

  • bad ground.

Any thoughts?

  • Hire an electrician!

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