A bypass is a passive component: nothing to configure, nothing to pair, and it never shows up in any app. You wire it in and it works. All the difficulty is in putting it in the right place.
If you are not yet sure a bypass is what you need, start with why the bulb glows or flickers — the 20 W threshold and the symptoms that separate this from other faults are there.
Before you open anything
Cut the supply at the breaker and confirm there is no voltage with a multimeter.
And here is the warning that genuinely matters for this particular job: do not trust the wall switch. In a no-neutral installation there is still voltage at points in the circuit with the light off — that residual current is precisely the cause of the problem you are here to fix. Switching the light off does not make the point dead.
Check as well that you have the right bypass. The one for a no-neutral relay and the one for a dimmer are not interchangeable.
Where it goes
In parallel with the load — that is, with the bulb. Its two wires go to the same terminals the lamp reaches.
The natural spot is inside the light fitting or in the junction box at the light point — not in the switch back box next to the device. At 39 × 23 × 13 mm it fits inside most ceiling fittings.
There is a practical reason it belongs up there rather than down at the switch: in most no-neutral installations the lamp return is not accessible in the switch box. And even where it is, that box is usually tight on space — and this component needs to breathe.
Step by step
- Cut the power at the breaker and verify it.
- Get to the light point. Take down the fitting, or open the junction box where the lamp wires arrive.
- Identify the load terminals: the two the bulb is connected to.
- Connect the bypass’s two wires to those same terminals. There is no polarity, so the order does not matter.
- Leave it ventilated. It draws under 4 W and dissipates that as heat. Do not press it against insulation or seal it into an airtight cavity.
- Close up, restore power and check both things: that the lamp comes on, and above all that it goes fully off. The second is what you came to fix.
If it still flickers afterwards
- Check it is in parallel and not in series. In series the lamp will barely light — an unmistakable symptom.
- Confirm it is the right bypass for your type of device.
- Try a different bulb. Some low-end LEDs flicker because of their own driver, bypass or no bypass.
- Rule out a different fault. If what actually happens is that the device restarts when you switch off, that is not a shortage of current but a voltage spike: you want an RC snubber.
- If the light does not switch off at all and the relay clicks without responding, that is not residual current but welded contacts: see when to replace the relay with a contactor.
Confirming the fix without going back up the ladder
If part of the symptom was the device dropping off the network when the light went out, the proof that the bypass worked is in the console: the last-seen timestamp stops coming and going and settles. It is a ten-second check in the browser instead of taking a ceiling fitting apart again to look.
Common questions
Can I put it in the switch box? Electrically it works if you can reach the same conductors, but you usually do not have the return accessible there, and space and ventilation are both against you.
Does the wire order matter? No. Passive, no polarity.
One per bulb? No — one per circuit. If three downlights share the same light point driven by one device, a single bypass covers them.
Can it be removed later? Yes, and it leaves no trace in any configuration. If you ever move to bulbs above 20 W, take it out and that is that.
Installation by a qualified person. If you are not comfortable working on the light point, use a registered electrician.