Possibly similar to Should a smart switch (that requires a neutral wire) cause my non-contact voltage tester to beep? but slightly different symptoms, and only on one switch.

After installing Leviton D26HD smart dimmer switches, running an NCVT-2P voltage detector pen around the front outside of the switch where the switch meets the face plate, it detects something on both sides half way up. But not on the top and bottom. And it doesn't detect anything on the other dimmer switch in the other room.

If I pull the switch out, the voltage detector beeps near the line and the neutral parts of the switch's sides (it has built-in wires, not terminals), but not near the load or ground.

Suggestions? Do I need an electrician to check?


1 Answer 1


Non contact voltage detectors are very sensitive and can be miss-leading. They detect the presence of power, not the amount of flow of power. Your smart dimmer is using a tiny bit of power at all times which is being routed thru the neutral, which is appropriate, but it's enough to trigger a non-contact voltage detector. If you really are worried about it, you need to get a digital multimeter (DMM)with an amp clamp on it that you can put around the neutral to measure the amps being used. It should be a very tiny amount, maybe not even measurable.

To be certain, can you provide a picture of the wiring in the box? It makes a difference whether this is a switch leg where the power goes to the fixture and then a cable to the box, or power goes to the box where the dimmer is and then a cable to the fixture.


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