Why Smart Switches can’t be used without neutral
One of the most common questions we get is « Why are there no Z-Wave On/Off switches that work in a 2-wire system », or « Which relays can I use without neutral ».
At which point we always recommend using a dimmer as these can work in a 2-wire system and explain that there are no switches available that can be used without neutral.
On the face of this doesn’t make sense. A dimmer appears to be a more complex device than a switch, so you’d expect it to be the other way around. I thought this would make a good blog post to explain just why this is the case and delve a little into how these devices actually work. Note that for the majority of this article I’m not talking about simple mechanical switches, I’m referring to smart switches or relays that can be controlled wirelessly.