There is one case where no auxiliary component fixes the problem, because the problem is that the relay is not up to that load. At that point you do not add a part: you change what opens and closes the circuit.
LED inrush current
Every LED driver has capacitors on its input. At the instant voltage is applied they are discharged, so for a few milliseconds they behave almost like a short circuit while they charge. That spike can be tens of times the nominal consumption.
The arithmetic is deceptive, which is why this fault catches people out. Ten 5 W downlights are 50 W: at 230 V, 0.2 A in steady state. An 8 A relay looks like enormous headroom. But those same ten drivers can draw tens of amps for an instant every time you switch on — and they all do it at once, because they share one relay.
Nominal current is not the figure that decides this. What decides it is how many drivers start simultaneously.
How it shows up
The damage is cumulative. Each switch-on erodes the contacts a little, and the failure appears weeks or months after an installation that was working perfectly. That gap in time is why almost nobody connects the two.
Symptoms:
- The light no longer switches off. The clearest one: the contacts have welded together and the circuit is closed for good.
- You hear the click but the load does not respond, or responds erratically.
- It started failing some time after installation, with nothing having changed.
A relay with welded contacts cannot be repaired. The device gets replaced. And if it is replaced with an identical one driving the same load, it will happen again.
Telling it apart from the other two faults
The three faults in this series look quite different once you look closely:
- If the bulb glows faintly or flickers with the light off, that is residual current: you need a bypass.
- If the device restarts when a motor switches off, that is a voltage spike: you need an RC snubber.
- If the light stopped switching off altogether and the relay clicks or does not respond, that is contact wear from current inrush. That is this article, and no parallel component will fix it.
The fix: keep the load off the relay
A contactor is an electromechanical switch built for exactly this: contacts rated to take repeated inrush, cycle after cycle, for years. It is a standard electrician’s part, cheap, and every installer has one.
The wiring changes the smart device’s role:
- The relay is configured in dry-contact (potential-free) mode, so it no longer switches mains through to the fittings.
- That dry contact drives only the contactor coil, which draws a few watts.
- The contactor is what opens and closes the lighting circuit, and what absorbs the inrush.
The device goes from switching amps to switching milliamps. It still controls the light exactly as before — from the app, a scene or a wall button — but there is no longer anything that can weld its contacts.
And an RC snubber on the coil
This is where the two parts of this series meet. A contactor coil is an inductive load — precisely the kind of load that generates a voltage spike when it is disconnected.
Without protection you will have solved the contact wear and imported the other problem: the device restarting every time it switches off. That is why the complete installation includes an RC snubber across the coil’s A1-A2 terminals — which is, literally, “as close as possible to the inductive load”, the rule from the snubber installation guide.
Before you get to a contactor
Not every case needs one:
- A higher-rated relay buys headroom — 8 A to 16 A, say. It helps, but be honest about it: more headroom is not a guarantee against a strong inrush, because what counts is not the nominal rating but how many drivers start at once.
- An NTC inrush limiter covers the marginal cases, where you are only a little over.
- Splitting the load across two circuits, where the installation allows it, halves the spike.
Once you have already replaced a device because of welded contacts, the contactor is the option that closes the matter.
What the console can and cannot tell you
Worth knowing the limits. The inrush spike will not appear on any graph: it lasts milliseconds and power measurement is sampled over far longer intervals. If you go looking for the spike in the history you will not find it, and that does not mean it is not there.
What the console is genuinely useful for is spotting an already-damaged relay without being on site: if a channel reports “off” while consumption keeps flowing, the contacts are welded. It is a contradiction the history puts in plain sight, and across an installation with several light points it saves walking round them one by one.
Both the app and the console work with Gen2, Gen3 and Gen4 devices, not only the models cited as examples here.
Installation by a qualified person. Fitting a contactor in the consumer unit and reconfiguring a relay to dry-contact mode is work for a registered electrician.