Humming noise

[Rich2774]

Odd thing happened to me today I installed dining room fixture for a customer 5 months ago. A chandelier with 5- 4watt LED bulbs on a dimmer , pretty basic . This morning I get the call that they are hearing humming sound coming from the fixture . Ok not uncommon right led bulbs, dimmers. When I get there I do hear the humming sound. So I start with removing each bulb one at a time . Still hear the sound now I remove the dimmer and I’m still hearing the humming. So now I have no lamps and removed the dimmer switch. Hot leg and switch leg now spliced together. Still making this sound . Now I take the fixture down check visual wiring . Reinstall and still hearing this sound . Very odd. So now I switch the neutral and switch leg in the ceiling and the sound goes away. In the ceiling box only 3wires switch leg , neutral and ground and each wire tested properly. Any ideas?

 

[synchro]

A suggestion is to remove the fixture and power it up with a 3-wire plug-in cord. After confirming that the noise is present, plug the cord into a GFCI receptacle and see if it trips. If it does trip then there may be current leakage from the hot to the ground wire, possibly caused by a bypass capacitor (although I think that would be unusual for a fixture with medium or candelabra screw-in sockets and no active electronics).
Ceramic capacitors are piezoelectric and so they can generate acoustic noise if driven by an AC signal.

 

[Flicker Index]

Are you sure the noise of electrical nature? Sometimes loose mounting can cause parts to resonate with micro vibration from airflow and such. A fixture like what you describe usually have nothing but metal and insulation. So, when you measure resistance from the frame to either of the wires, it should not register any reading on your ohmmeter.

 

[Fred B]

Are you sure the noise of electrical nature? Sometimes loose mounting can cause parts to resonate with micro vibration from airflow and such. A fixture like what you describe usually have nothing but metal and insulation. So, when you measure resistance from the frame to either of the wires, it should not register any reading on your ohmmeter.

Had a service call once for buzzing noises in light fixture everytime it is turned on and kept buzzing for several minutes after it was shut off. Had to get a specialist in to help with that one. A small begining hive of honey bees got a beekeeper