I'm trying to upgrade a light switch and would be grateful if someone could tell me what goes where. I've tried various combinations but the light either does not turn on or stays on permanently.
Wiring – Simple light switch wiring upgrade to new switch – NO NEUTRAL
lightswitchwiring
Related Solutions
If all you have is one wire entering the switch, then the power for the switch might come from the light, and you just have a switched hot.
The white wire should be marked with tape to indicate it's not being used as a neutral.
Unfortunately, if this is the case, then you don't have a neutral available at this switch which is necessary for most of these automation switches. If there are other switches in this box it might be possible to re-route the power for this light, but I'd need to know more about where the power is coming from, what else is there, and how the light is connected in the ceiling box to help. Otherwise, the only way to this would be to run a new wire to the switch location -- either a new 14/3 from the light (so you have hot, neutral and switched hot), or a new power feed with 14/2 from the panel.
Too bad I haven't updated answer when I rewired everything - but better late, then never, right? Here are the answers to my questions:
- White wire is neutral in US in most cases... so it was in my case.
- Basically, two whites were neutrals for two different circuits. I bought Voltage detector and separated right white wire by turning off circuit for lights - the other white still had electricity running through it so I was able to figure it which white/neutral I needed
- Yeah, I just cut it, add in neutral connecting from the switch and then put cap on
- For this you need Voltage Meter, there are quite few tutorials on YouTube that explain how to figure out which wire is which with Voltage Meter.
Best Answer
The wiring in your wall is called a "traditional switch loop". The two wires present (besides ground) are always-hot (we hope, the white) and switched-hot (we hope, the black). Note that neutral is NOT present in this box.
This is a case of white being used as a hot wire because the cable only has 2 conductors. Modern Code requires a re-tasked white wire be marked with paint or tape to indicate it is not a neutral. That is also why they are supposed to make it always-hot; so in all switch positions it will test out as hot.
The switch wants always-hot on black and switched-hot on red. However, it also wants neutral on the white wire. This box does not have a neutral. You cannot use this switch here today.
There are two ways to make this work:
Take it back and get a smart switch that doesn't need neutral
They do exist. They either leak current through the light bulb, which doesnt play well with LEDs, but you can mitigate this by adding a special capacitor made by Lutron IIRC. Or, they received permission from UL (Underwriters Laboratories) to use certain particular tricks which allow them to use ground. This latter type is marked "Requires ground".
Replace the cable in the wall with a /3 cable, and reassign the colors.
This is mandatory for any newly installed switch loops after 2011. In that case, you rewire it so black is always-hot, red is switched-hot, and white is true neutral. The colors will match the switch.