I’m newish to Home Assistant and am still installing mostly Z-Wave switches. My garage is the one switch in the house that doesn’t have a neutral and it’s not easy to run a neutral to it. I recently learned about Shelly devices and I think they can help me out here.
Ideally, what I’d like is a smart switch with a motion detector, in the garage. I’m looking for some advice for the best way to approach this.
As far as I understand, I think these are my options:
Regular switch + Shelly relay = Smart Switch, no motion
Motion switch = Motion, but not smart
Motion switch + Shelly relay = Motion and smart (Is this possible?)
Regular switch + Shelly relay + battery-powered motion sensor = Motion and smart. Home Assistant could then trigger the light when motion is detected. I know this is likely overly complex, but isn’t what we like to do?
Any recommendations on an approach to do this (or not) would be very much appreciated!
You could install the motion sensor near the light fixture, where the neutral will definitely be available & there’s a good chance that permanent live will be there too. Hell, for a garage, I’d just plop in a dumb motion sensor & hardwire it directly to the light circuit with no smarts at all.
I guess it depends on your garage layout - it would work fine if the garage door & the internal door are on adjacent walls. Not so much if they’re on opposite walls (you’ll probably need 2 motion sensors for that).
If you don’t like the above idea, then go with option 4. ZWave battery devices should last a couple of years before requiring a battery change.
I tend to agree, it is just in the garage so a dumb motion sensor is more than adequate. But who wants to be adequate?
Also, I didn’t know that there is a neutral at the fixture itself. Shows how much I know. It’s not worth the effort, in this case, but it is good to know!
I think “overly complex” was a mis-statement. I’m spoiled and used to simply replacing a switch with a smart switch and I’m done.
Now I’m trying to figure out which Shelly device to use and do I need to use a bypass with it, and then I learn that there is likely a neutral by the fixture itself. Not that it is so hard to do that.
So, to me, it is getting overly complex. I know, objectively, it really isn’t complex at all.
How could the light turn on without a neutral? All light fixtures will have a switched hot and a neutral. But not usually a unswitched line. I have a couple of battery-powered sensors in my garage (because one doesn’t cover the whole space) and an automation to turn on the light when motion is detected. I change the batteries once a year.
I’m asking this genuinely, aren’t there lots of lights without neutrals? I thought that before it became standard code in the U.S., that lights didn’t have to have neutrals. They had a Line and Load and a Ground. At least that is my understanding of it. Isn’t that why Shelly and others make relays/smart switches that don’t need a neutral?
I hope I’m not misunderstanding your question. I think I know enough to install smart switches, under normal circumstances, but otherwise I might know just enough to be dangerous!
Plus, all the other switches in my house have Line,Load,Neutral,Ground, so that this one, in the garage didn’t, I was confused and thought they just didn’t bother with it.
In 1962, the NEC required a ground wire in all receptacle circuits. Neutral wires were inherently required for all circuits. Note: Romex cables used in almost all home installations use designations like 14/2 and 14/3. These cables have 14 gauge (15 Amp) circuits and all Romex cable also have a ground wire; usually bare copper. 14/2 means two conductors plus ground.
In 2011, neutral in switch boxes were required.
Before 2011, this kind of light circuit was allowed:
There is no neutral wire in the switch, which is where you would use a “no-neutral” switch like the Shelly. A “no neutral” switch has a small processor inside like the ESP8266 or similar. Since the processor only draws a few mA of current, the load acts as a “neutral”. In the above circuit, if you remove the light, the Shelly switch will go offline.
Since 2011 neutral wires are required almost everywhere. An exception is if a wall-switch controls a half-hot receptacle. (A half-hot receptacle is one where the top half is always hot and the bottom half is controlled by a wall switch. Think floor lamps.) The receptacle has a neutral wire but the switch doesn’t. Another exception is in 3- or 4-way switching where another switch in the circuit does have a neutral.
The practical reality is that electrical contractors probably only buy 14/3 Romex cable for all home wiring. The cost of using 14/2 where 14/3 was required is just not worth stocking 14/2.
BTW- 2-way or 3-way switches. In the US a circuit where two switches control the same light is called “3-way”. Everywhere else it “2-way”. Other than the name the circuits are identical.
