Weird Lighting Problem

CMHbob

Just bought this house and one room has light switch but the ceiling opening is covered by a standard plate. The room needs a light so I installed a new fixture and bulb, flipped the switch and nothing happened. Not the result that I wanted.

With a voltage sensor, I tested the line (black) wire. With the switch on, it is hot. With the switch off, it is not hot. Then I tested the neutral (white) wire. With the switch on, it is not hot. With the switch off, it is not hot.

Then I checked the central distribution box. I located the breaker controlling the switch in question. Following normal safety precautions, I reseated both the black and white wires for this circuit inside the box. I flipped the switch and nothing happened.

Any ideas what is causing this problem? I am not afraid of electrical wiring so I would appreciate any suggestions to fix it.
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CMHbob

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HouseHelper

1. Try a new bulb
2. Check the wiring of the new fixture
3. Check the wiring at the switch

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"Life is hard. Life is harder when you're stupid." John Wayne

AllanJ

What is the voltage between the black wire and the white wire? Between the black wire and ground? Between the white wire and ground? Repeat with switch in each position.

Maybe the white wire up in the ceiling is not connected to anything because the former owner revised the wiring.

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CMHbob

This room originally was a "lean-to" garage based on the layout of similar homes in the neighborhood. It was open on two sides with the roof extending over a concrete pad. It obviously was remodeled at some time in the past. Allan, I think you may be on to something. I'll check it out.
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CMHbob

Visit my Blog to learn about my latest project and reno tips.

Red Squirrel

Sound silly, but yes try a new bulb. I have used a light to test a circuit at times and pulled hair as to why it wont work. Turns out the bulb was burnt!

Saturday Cowboy

since this was originally outside it might be on gfci

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Ragged Trousered Philanthropist


Please follow the code - its there for your safety no matter how inconvenient.

CMHbob

1. Try a new bulb
2. Check the wiring of the new fixture
3. Check the wiring at the switch

Installed tested bulb - no change
Moved fixture to another ceiling box - it works as expected
Replaced wall switch with new one - no change

I put the new ceiling fixture back and ran a 14GA (insulated) wire from the white (neutral) wire on the fixture to a nearby outlet. I connected it to the neutral (white) wire on the outlet and flipped the switch. It worked - the light turned on/off with the switch. Yaaah!

Now I am thinking there is a hidden electrical box in the ceiling and the white wire connection is loose or the wire nut has failed.

The ceiling is finished with 12x12 fiber board squares and were white when installed. Now they have yellowed with time and it will be hard to match the color when I pull them down. This is turning out to be a lot more work than I anticipated.
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CMHbob

Visit my Blog to learn about my latest project and reno tips.

klavatar

Speaking of GFCI, I had an electrician come by and replace all my outlets less than 6ft from a faucet to GFCI outlets. Turns out he installed one backwards (he connected the line to the load end and load to live on the GFCI module), and the result was that the outlet and all the downstream circuits were hot and the green GFCI light was lit, but the multimeter showed that it only had about 14V AC. Took me a while to figure it out, but once I flipped it back, everything started working again.

So sometmes the fact that the outlet is hot does not mean it has enough juice. Not sure if it's relevant in this case, but certainly good to know.