PROBLEM BOTTOM LINE: I installed some lights in my basement. There is voltage between the metal light cans and a nearby copper pipe. I can't figure out why.
DETAILS: I recently had some HVAC work done in an unfinished part of my basement. I had to remove three lights that were in the way. There was a single run of NM-B that fed into a metal junction box that then split into three NM-B lines that fed each of the three lights.
Two days ago I hooked up three recessed light cans to the three lines. Black to black, white to white, and ground-to-ground. Closed everything up, flipped on the breaker, and turned on the lights--and they look great.
Here's where I'm stumped. I used my multimeter to check the voltage between the metal junction box exterior or the exterior of the light cans and a nearby copper pipe. What I expected was 0V. What my meter read was 105 volts with the light switch off and 50-something volts when the light was on (note that it's an illuminated switch). Huh. Checked other junction boxes and the copper piping and they read 0 volts as I would expect. I doubled checked all my wiring. Checked for continuity between the hot or neutral and the junction boxes/can housings--nothing. There is ground continuity from all the cans to the metal junction box feeding the lights.
I then checked how the entire circuit was wired from the main panel. It goes main panel-->metal conduit with white and black wires inside-->metal junction box-->armored flexible conduit feeding into a metal junction box with a toggle switch...
The toggle splits two ways:
(1)-->single NM-B to the metal junction box feeding the three lights
(2)-->single NM-B to an outlet
The outlet had an open ground. The bare copper wire in the NM-B wasn't connected to anything. I stripped the wire so I could get to the copper wire, connected that to a new GFCI and bonded that to the metal outlet box. I wired the black and white appropriately. Outlet now shows it's grounded.
The original problem was not fixed, so I opened up the toggle switch. It's weird in there. The metal flexible conduit from the service panel feeds into the metal switch/toggle junction box. The white wire from that connects to one side of the switch. The NM-B neutral feeding the outlet is connected to the other side of the switch as is the neutral from the NM-B feeding the lights.
The hot wires from the metal conduit, the outlet, and the lights are all merged in a single wire nut.
The bare ground wire from the outlet and light NM-B wires aren't connected to anything--not the switch nor the metal toggle/switch junction box.
Lastly, there are energized wires that run pretty close to NM-B feeding the lights. I've heard that this can cause ghost voltages, but my multimeter doesn't have LOZ capabilities.
HERE'S WHAT I'M CONSIDERING:
1) Install a new toggle switch--attach hot from service metal conduit into a 3 way wire push connector. Run one hot to one side of the switch. Run the other hot directly to the hot feeding the outlet. Attach hot from NM-B feeding lights to the other side of the toggle switch.
2) Connect the neutrals from the main feed, outlet, and lights together.
3) Connect grounds from the outlet NM-B and light NM-B together and then to the switch toggle ground and bond that to the toggle junction box.
I know it would be easier to picture with a diagram but I suck at drawing.
Any thoughts?
DETAILS: I recently had some HVAC work done in an unfinished part of my basement. I had to remove three lights that were in the way. There was a single run of NM-B that fed into a metal junction box that then split into three NM-B lines that fed each of the three lights.
Two days ago I hooked up three recessed light cans to the three lines. Black to black, white to white, and ground-to-ground. Closed everything up, flipped on the breaker, and turned on the lights--and they look great.
Here's where I'm stumped. I used my multimeter to check the voltage between the metal junction box exterior or the exterior of the light cans and a nearby copper pipe. What I expected was 0V. What my meter read was 105 volts with the light switch off and 50-something volts when the light was on (note that it's an illuminated switch). Huh. Checked other junction boxes and the copper piping and they read 0 volts as I would expect. I doubled checked all my wiring. Checked for continuity between the hot or neutral and the junction boxes/can housings--nothing. There is ground continuity from all the cans to the metal junction box feeding the lights.
I then checked how the entire circuit was wired from the main panel. It goes main panel-->metal conduit with white and black wires inside-->metal junction box-->armored flexible conduit feeding into a metal junction box with a toggle switch...
The toggle splits two ways:
(1)-->single NM-B to the metal junction box feeding the three lights
(2)-->single NM-B to an outlet
The outlet had an open ground. The bare copper wire in the NM-B wasn't connected to anything. I stripped the wire so I could get to the copper wire, connected that to a new GFCI and bonded that to the metal outlet box. I wired the black and white appropriately. Outlet now shows it's grounded.
The original problem was not fixed, so I opened up the toggle switch. It's weird in there. The metal flexible conduit from the service panel feeds into the metal switch/toggle junction box. The white wire from that connects to one side of the switch. The NM-B neutral feeding the outlet is connected to the other side of the switch as is the neutral from the NM-B feeding the lights.
The hot wires from the metal conduit, the outlet, and the lights are all merged in a single wire nut.
The bare ground wire from the outlet and light NM-B wires aren't connected to anything--not the switch nor the metal toggle/switch junction box.
Lastly, there are energized wires that run pretty close to NM-B feeding the lights. I've heard that this can cause ghost voltages, but my multimeter doesn't have LOZ capabilities.
HERE'S WHAT I'M CONSIDERING:
1) Install a new toggle switch--attach hot from service metal conduit into a 3 way wire push connector. Run one hot to one side of the switch. Run the other hot directly to the hot feeding the outlet. Attach hot from NM-B feeding lights to the other side of the toggle switch.
2) Connect the neutrals from the main feed, outlet, and lights together.
3) Connect grounds from the outlet NM-B and light NM-B together and then to the switch toggle ground and bond that to the toggle junction box.
I know it would be easier to picture with a diagram but I suck at drawing.
Any thoughts?
