Hey everyone,
I recently got some smart switches from AliExpress and tried hooking them up to my existing setup. The switch I’m replacing only has two wires. I connected the live wire to L-in and ground to N-in, and it does work, but the light barely glows.
Is this an issue with my wiring, or is the product itself not up to the task? Or do I absolutely need all 4 wires for this to work properly?
Thanks for any advice!
Smart switches are pretty common around Boston… is that where you’re at?
SafeHavenExpert3 said:
Smart switches are pretty common around Boston… is that where you’re at?
I thought the person who posted was just trying to save a few bucks with AliExpress gear!
@Harrison
Fair point, but maybe not the best way to save money.
In simple terms, the wires labeled “in” are for power from the wall, while the “out” wires go to the device.
L-in = Line in
L-out = Line out
N-in = Neutral in
N-out = Neutral out
The ‘S’ terminals are for an external physical switch, but in many cases, those won’t be used.
@Dan
Got it… so the wall switch should really have 4 wires? Does that mean 2 wires alone won’t work?
Jared said:
@Dan
Got it… so the wall switch should really have 4 wires? Does that mean 2 wires alone won’t work?
Ah, sorry about the mix-up. Yes, typically only the live wire goes to the switch, with neutral elsewhere. But to use this smart switch fully, you’ll need all 4 wires where the device is. It’s a bit tricky, but it should work better.
Jared said:
@Dan
Got it… so the wall switch should really have 4 wires? Does that mean 2 wires alone won’t work?
You probably don’t have a neutral wire in the wall, so it sounds like your setup only switches the live wire. This switch may never work correctly without neutral. Try looking for ‘no neutral required’ smart switches.
That smart switch needs a neutral wire, which you don’t have (since you mentioned only two wires). Find a switch specifically labeled ‘no neutral required.’ The one in your picture needs both neutral and line from the box, plus a line to the device. Neutral-free ones can work with just live and load.
@Ryan
Yes, and please don’t connect ground to neutral at the switch—it’s a major safety hazard. If you’re not sure, it might be best to get an electrician’s help.
Ricardo said:
@Ryan
Yes, and please don’t connect ground to neutral at the switch—it’s a major safety hazard. If you’re not sure, it might be best to get an electrician’s help.
Using AliExpress electrical parts isn’t the safest choice. If anything goes wrong, insurance may not cover it.
@Louis
Just a heads-up: insurance usually has to cover claims, even if they’re against policyholder errors. But yes, using devices that aren’t UL rated may pose risks. It’s best to stick to certified hardware for peace of mind.
@Collin
Alright, do what you like, but remember the risk with uncertified products. Safety first!
Louis said:
@Collin
Alright, do what you like, but remember the risk with uncertified products. Safety first!
Let’s not twist this. No one is saying to go ahead and use sketchy devices. Just pointing out that insurance will still cover accidents. But yeah, AliExpress gear is risky.
@Ryan
Thanks a lot, I’ll look for a switch that says it’s for setups without a neutral.
If you’re in North America, these cheaper products from abroad aren’t certified here and could be risky. If something happens, there’s a chance insurance won’t cover it. Use a certified product instead, like those from Shelly (UL Certified Relays - Shelly USA). And, as others have mentioned, never use ground as a substitute for neutral.
If you’re only seeing 2 wires in the box, that switch likely only interrupts live or neutral power. A smart switch requires ‘in’ and ‘out’ connections for its relay to work. If this isn’t making sense, it might be time to consult someone with experience.
Yes, you’ll need both live and neutral from the wall to make this work, so all 4 wires are needed.
If you only have two wires, look for a smart switch that doesn’t need a neutral wire. It’ll work better for your setup.