Shelly relay clicks but the light or appliance doesn't turn on
The relay clicks and the app says On, but nothing gets power. Check what the app and web page show, then the timers, the other controls and the protections.
Checked
Gen4
Start here
What are you seeing?
Pick the closest match and we'll point you to the fix most likely to sort it.
When a Shelly relay clicks, it has switched. If the light or appliance still
gets nothing, the reason is usually outside the Shelly: the load itself, or how
the circuit runs through the relay.
The rest are settings. A timer, a schedule or a protection can switch the
output straight back off, and the device's web page shows which.
Before you start
Everything here is done in the Shelly app or a browser. Checking the wiring, the circuit or the load's supply is a job for a licensed electrician. Don't open the wall plate.
Quick checks first
Run these checks before moving on to the fixes.
Checklist0 of 3 checked
Check what the Shelly says
Open the device's web page or the app and look at the output. If it says Off, the Shelly hasn't switched on, and the fixes for turning it on are in the switch guide.
Check the model
The 1PM, 2PM and 1PM Mini Gen4 measure the power they switch, so they can show whether the load is drawing anything. The Shelly 1 and 1 Mini Gen4 can't.
Check the load itself
A lamp or appliance with its own switch turned off draws nothing, and a blown globe looks the same as a Shelly that didn't switch.
Fixes, most likely first
Work down the list and stop when it's fixed.
1
Most likely for you
The relay isn't wired to feed the load
How to tell. A Shelly 1 or 1 Mini Gen4 clicks and shows On, and responds normally, but the load never comes on. Shelly describes their relays as potential-free: they close a circuit but supply no power themselves.
Ask an electrician to check the load circuit
Powering the Shelly doesn't power the load. The load's supply has to run through the relay, and checking that is wiring work for a licensed electrician. Tell them it's a Shelly 1 Gen4 or 1 Mini Gen4 with a potential-free relay.
Did this fix it?
2
Most likely for you
The light or appliance isn't working
How to tell. On a 1PM, 2PM or 1PM Mini Gen4, the output shows On and the voltage reads normally, but the power stays near 0 W. The Shelly has switched; nothing on the circuit is drawing power.
Read the power while it's on
Open the device's web page with the output on. The home screen shows the power in watts beside the voltage.
Try a globe or appliance you know works
Swap the globe, or plug a lamp you know works into the switched power point. If that works, the old globe or appliance is the fault.
Call an electrician for the rest
If a working globe or appliance still draws nothing, the fault is in the circuit, and that's for a licensed electrician.
Did this fix it?
3
Most likely for you
An Auto off timer switches it back off
How to tell. It comes on, then goes off after the same time every time, however you turned it on. Auto off applies to every On, including a schedule's.
Check the timers
On its web page, go to Settings, click the output, then click Timers.
Turn off Auto off, or make it longer
Under Auto OFF, untick Enable, or set a longer delay, and click Save. In the app, it's the Timer tab in the device's settings.
Did this fix it?
4
Most likely for you
Something else is switching it
How to tell. It goes off at times nobody touched it. Shelly gives a schedule, the app, a wall switch and a scene no priority over each other: the last command wins.
Look at the actions and schedules
On its web page, go to Settings and click the output. The Actions and Schedules tabs list everything set up to switch it.
Check the app's history
The Activity log in the app records every On and Off with its date and time, which shows when it switched, so you can match it to a schedule or scene.
Check scenes and other apps
A scene in the Shelly app, Home Assistant or a script on another Shelly can switch it too. Look there for anything that turns it off.
Did this fix it?
5
Most likely for you
An output protection switched it off
How to tell. On a 1PM, 2PM or 1PM Mini Gen4, the output turns off while the load is running, or turns off again as soon as you turn it on. The Shelly 1 and 1 Mini Gen4 have no output protections to set.
Check the limits
On its web page, go to Settings, click the output, then Output protections. Check the Overpower, Overcurrent and Overvoltage values aren't below what the load normally draws.
Don't raise them past the rating
Shelly caps Overpower at the model's maximum current times its maximum voltage. A load that needs more than that is the next cause.
Did this fix it?
6
Most likely for you
The 2PM Gen4 is set up for a cover
How to tell. The app or web page shows open, close and stop instead of two separate outputs. In its cover profile, Shelly runs both channels together as one motor control.
Change it back to the switch profile
If the two outputs run two separate loads, change the device's profile from cover to switch in its settings. If it does run a blind or curtain motor, leave it and check the motor with whoever installed it.
Did this fix it?
7
Most likely for you
The load is bigger than the model can switch
How to tell. The load's rating plate shows more than the model's limit: 16 A for the 1 and 1PM Gen4, 8 A for the 1 Mini and 1PM Mini Gen4, and 10 A per channel for the 2PM Gen4.
Ask an electrician
A load over the limit needs a different device, or a contactor that the Shelly switches instead. Both are wiring work for a licensed electrician.
Did this fix it?
On your device
Shelly 2PM Gen4Two outputs, two limits
Check each channel and the total
Shelly rates the 2PM Gen4 at 10 A for each channel and 16 A for the two together, and 3 A for a motor.
Shelly uses it for the relay on the Shelly 1 and 1 Mini Gen4. The relay carries no voltage of its own; it only connects whatever circuit runs through it.
The app's Activity log lists every On and Off with its time. Matching the time to your schedules and scenes usually finds it.
No, it's a dimmer, not a relay. If it shows On and the light stays dark, see the guide on lights that flicker or glow.
