You flick the garage lights on and the whole circuit dies. Or worse, the lights work fine for three weeks and then start tripping at random, usually on a wet Tuesday.
It is a common problem and it is almost never the LED panels themselves. Here is what is actually happening, what you can safely check yourself, and where the line is between investigating and calling someone.
First, know which device tripped
This tells you most of what you need to know, and people routinely skip it. Open the consumer unit and look at what has moved.
An MCB
A miniature circuit breaker protects the cable from too much current. Each circuit has its own, usually labelled for lights, sockets, cooker and so on.
An MCB trips for two reasons. Either too much load has been drawn over time, or there has been a sudden very high current such as a short circuit.
An RCD
A residual current device watches for current leaking to earth, typically at a threshold of 30 milliamps. It is there to protect people rather than cables, and it is the device that saves you if a faulty appliance puts voltage somewhere it should not be.
An RCD tripping usually means current is escaping to earth somewhere. Moisture, damaged insulation, or a faulty appliance are the usual suspects.
An RCBO
Both functions in one device, protecting a single circuit. Modern consumer units often use these, which is helpful because a trip points you at one circuit rather than half the house.
Why LED lighting causes nuisance tripping
Inrush current
This is the big one and it surprises people, because LEDs draw so little power in normal use.
Every LED driver contains capacitors, and at the instant you switch on, those capacitors charge. For a few milliseconds the current drawn is far higher than the running current. One driver is nothing. Twenty drivers on one circuit, switching simultaneously, can briefly pull a surge large enough to trip a sensitive MCB.
The telltale sign is that it only ever trips at the moment of switching on, and never while the lights are running. If that is your pattern, inrush is the likely cause. An electrician can address it by splitting the load across circuits, staggering the switching, or fitting a breaker with a more appropriate tripping characteristic.
Cumulative earth leakage
Switched mode power supplies, which is what LED drivers are, each leak a tiny amount of current to earth by design. It is normal and harmless individually.
The problem is that leakage adds up. Put enough drivers on one RCD, along with a fridge, a freezer, a charger and whatever else lives in the garage, and the total can creep toward the 30 milliamp threshold. Then anything else joining the circuit tips it over, and the trips look completely random.
Moisture
Very common in detached and uninsulated garages. Condensation inside a fitting, water finding a junction box, or damp reaching a connection all create a path to earth.
The giveaway is seasonal or weather linked tripping. If it started in November and never happened in July, look at moisture before anything else.
A genuinely faulty driver
Drivers are the component most likely to fail in any LED system. A failing one can leak to earth or short internally. If the trips began after years of trouble free operation with no other changes, a failing driver is a reasonable suspicion.
Circuit overload
Less likely with LED lighting, which draws very little. Much more likely if your garage lighting shares a circuit with a compressor, a welder, a heater or an EV charger. The lights get blamed because they are the thing you switched on, but the load was already close to the limit.
What you can safely check yourself
- Note exactly when it trips. On switch on, at random, or under load.
- Note whether it is an MCB or an RCD that operates.
- Unplug everything else in the garage and try the lights alone.
- If the lighting is a plug in kit, try it on a different circuit entirely, such as an indoor socket, and see whether the problem follows it.
- Look for visible water ingress, damaged cable or scorching.
- Check whether the trips correlate with weather.
That information is genuinely useful to an electrician and will save you money on diagnosis time.
Where to stop
Call a qualified electrician if any of these apply.
- The circuit is hardwired rather than plugged in
- It trips repeatedly, or trips again immediately after resetting
- There is any smell of burning, discolouration or scorching
- The RCD will not reset at all
- You would need to open the consumer unit, a junction box or a fitting to investigate further
- The installation is old, or you do not know when it was last inspected
Repeated tripping is a protective device doing its job. Resetting it over and over without finding the cause is the wrong response, and taping a breaker or swapping it for a larger one is genuinely dangerous.
In England and Wales, new circuits and consumer unit work in a garage are notifiable under Part P of the Building Regulations. Certification also matters for insurance, particularly in a commercial unit.
Reducing the chances when you install
- Do not put all your lighting on one circuit if the installation is large
- Separate lighting from heavy loads such as compressors, heaters and EV charging
- Use fittings with an IP rating appropriate to how damp the space actually gets
- Ventilate the garage to reduce condensation
- Have the installation inspected and certified when it is done
- Keep the driver somewhere ventilated and dry, not buried in insulation
Frequently asked questions
Can LED lights really trip a breaker?
Yes, usually through inrush current at switch on or through cumulative earth leakage across several drivers, rather than through drawing too much power in normal use.
Why does it only trip in winter?
That pattern points strongly at moisture. Condensation inside fittings or damp reaching connections creates a path to earth that disappears when the garage dries out.
Is it safe to keep resetting the breaker?
No. A device that trips repeatedly is telling you something is wrong. Find the cause rather than resetting around it.
Will a bigger breaker fix it?
Fitting a larger breaker removes the protection the cable needs and is unsafe. The correct answer is finding out why the existing one is operating.
Planning a new install and want to get it right first time? See our hexagon lighting range, or get in touch with the details of your space and we will tell you what the load will be.