Hi I have a WiFi dimmer switch that I want to replace an existing dimmer switch. Based on the picture the existing wiring doesn’t have a neutral, only line and load. But the WiFi dimmer has line load and neutral. I set it up and the app saw the switch and said it was working but the lights didn’t turn on. Any advice?

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  • Can you post a clear photo looking squarely into the back of the box please? Also, how attached are you to Wi-Fi dimmers specifically? – ThreePhaseEel Mar 21 '20 at 15:40
  • Yeah, also, did you know that your camera/whatever tech is posting thumbnails of the pics, like 320x200? If you can't troubleshoot that right now, it may still work if the photos are carefully framed and carefully lit. – Harper - Reinstate Monica Mar 21 '20 at 20:24
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    Oh and that thing you did, hooking random wires up until something started to work? (as pictured, both wires are plainly in the wrong place, yet, it made the switch power up, didn't it? :) ... don't ever do that. There are many combinations which will work and will kill you. When you lack a clear indication of what to do, either research/skillup, or ask for help. – Harper - Reinstate Monica Mar 21 '20 at 20:33

Fro you photos, you attached the dimmer’s neutral to the load (light). This is allowing the dimmer to power itself. Meanwhile, the load wire from the dimmer is unconnected; this wire would actually control the light. This will not work.

Bottom line: without a neutral wire in the switch box, you cannot make the dimmer work safely. (You could connect the neutral wire to ground, but this is a serious code violation and could potentially electrocute (kill) someone!)

  • There are dimmers that do not require a neutral. you might be able to exchange yours. Stay safe out there doxyLover. – JACK Mar 21 '20 at 16:26
  • It's hard to say beause the wires were obviously carefully remarked, but I can't see if that was done by OP or "the last guy". If the latter, then OP has connected neutral to Line In, which is bad. I suspect OP was "trying every combination" and stumbled on this one, which produced the partial success of allowing the switch itself to power up. OP reasoned that partial success must mean most things are right (incorrect). – Harper - Reinstate Monica Mar 21 '20 at 20:36
  • Hi I found this site about WiFi dimmer switches that don’t need a neutral. Is it legit? alarmgrid.com/faq/…. Also the red taped wire is from the circuit I don’t want to create a fire hazard bc I’m lazy. – Tonkadog Mar 22 '20 at 15:21
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    @Tonkadog Smart switches that don’t use a neutral tend to work poorly with CFL and particularly LED bulbs. The problems you will see include flickering or glowing dimly when off and not being able to go full bright. The former problem is due to the switch getting power when off by trickling current through the load. An incandescent bulb is so inefficient that this will not cause a visible glow but an LED will tend to flicker or glow dimly from that trickle. – DoxyLover Mar 22 '20 at 23:50
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    @Tonkadog, I have the Lutron Caseta dimmers and they work great with all my bulbs and don't require a neutral. However, I do believe the require a good ground, which seems to be another thing you are missing. If you have a metal box, it might be grounded via conduit, but that's something you would need to verify. – JPhi1618 Mar 23 '20 at 16:45

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