LED lights that glow faintly after being switched off are experiencing a common issue called LED ghosting. It happens when a small amount of residual electrical current continues to reach the bulb through the wiring, switch, or driver circuit after you turn the light off.
The cause is usually an incompatible dimmer switch, an illuminated or smart switch drawing standby current, or capacitive coupling in the wiring. Byrd Electrical provides LED lighting installation and fault diagnosis across Melbourne and Bayside. This guide explains why LED ghosting happens, whether it’s dangerous, and how to stop it.
Why LED Lights Glow When Switched Off
LED ghosting occurs because LEDs require extremely low power to produce visible light. A tiny residual current that would be invisible in an old incandescent bulb is enough to make an LED glow faintly.
Unlike halogen or incandescent bulbs that need significant wattage to heat a filament, LEDs use semiconductor technology that responds to currents measured in milliwatts. According to the Australian Government’s lighting guidance, LEDs use about 75% less energy than halogen bulbs. That efficiency is what makes them glow from even the smallest stray current.
In my 15 years working on lighting installations across Melbourne, LED ghosting is one of the most common questions I get after a halogen-to-LED upgrade. The good news is that it’s almost always fixable once you identify the source.
What Causes the Residual Current
The faint glow reaching your LED comes from one of several sources. Identifying which one applies to your home determines the fix:
Incompatible dimmer switch
This is the number one cause I see in Melbourne homes. Older trailing-edge or leading-edge dimmers designed for halogen loads cannot fully cut power to an LED circuit. The dimmer leaks a small current even in the off position, and the LED picks it up. Homes across Brighton, Camberwell, and Toorak that have upgraded to LED downlights but kept the old halogen dimmer are the most common cases. Replacing the dimmer with an LED-compatible model resolves this immediately.
Illuminated or smart switch leakage
Switches with a built-in indicator light (a small neon or LED glow in the switch plate) draw a trickle of current through the circuit to power that indicator. This current passes through the LED fitting, causing it to glow. Smart switches without a dedicated neutral wire behave the same way. They must draw standby power through the load circuit, which keeps the LED faintly lit.
Capacitive coupling in the wiring
When the live wire and switched wire run parallel to each other over a long distance, such as from a switchboard to a ceiling fitting in a two-storey home, a small voltage can be induced from the live conductor onto the switched conductor. This phantom voltage is enough to activate the LED’s driver. Older homes in Sandringham, Elsternwick, and Malvern with long cable runs through ceiling cavities are more prone to this.
Stored energy in the LED driver
Every LED bulb contains a driver circuit with capacitors that store energy to smooth the electrical supply. When you turn off the light, these capacitors don’t discharge instantly. They release their stored charge slowly through the LED, producing a brief afterglow that fades over seconds to minutes. This type of glow is harmless and temporary.
Low-quality LED bulbs
Cheap LED bulbs with poorly designed driver circuits are more susceptible to ghosting. The driver doesn’t dissipate residual energy efficiently, leaving enough current to produce a visible glow. Replacing the bulb with a quality product from a reputable brand often solves the problem without any other changes.
Is LED Afterglow Dangerous?
LED ghosting is not dangerous in most cases. The residual current involved is extremely low, far below levels that create a fire or shock hazard.
However, there are two scenarios where the glow signals something that needs professional attention:
- The glow is bright or consistent, not a faint dim. If the LED is producing noticeable light (not just a faint shimmer), the leakage current is higher than it should be. This could indicate a wiring fault, an incorrectly connected neutral, or a failing switch. A licensed electrician should inspect the circuit.
- The glow is accompanied by flickering, buzzing, or a warm switch plate. These additional symptoms point to an electrical fault rather than simple ghosting. Buzzing or heat at the switch suggests arcing or a loose connection, which is a fire risk.
If the glow is a barely visible, faint shimmer that fades after a few minutes, it’s the stored energy in the driver dissipating. That’s normal LED behaviour and safe to leave.
How to Fix LED Ghosting
The right fix depends on the cause. Here is a decision framework:
| Cause | Fix | DIY or Electrician? |
| Old halogen dimmer on LED circuit | Replace with a trailing-edge, LED-compatible dimmer | Electrician (switch replacement involves mains wiring) |
| Illuminated switch with indicator light | Replace with a standard switch or disconnect the indicator lamp | Electrician |
| Smart switch without neutral wire | Replace with a neutral-required smart switch, or install a bypass capacitor | Electrician |
| Capacitive coupling on long cable runs | Install a bypass capacitor (snubber) at the light fitting | Electrician |
| Stored energy in LED driver (brief afterglow) | No fix required. This is normal and fades in seconds to minutes | N/A |
| Low-quality LED bulb | Replace with a reputable brand LED | DIY (bulb swap only) |
| Suspected wiring fault (bright glow, buzzing, heat) | Full circuit inspection and repair | Electrician (urgent) |
A bypass capacitor is a small component wired in parallel with the LED fitting. It provides a path for the residual current to discharge through, diverting it away from the LED. One capacitor per switch circuit is usually sufficient. This is the standard solution for ghosting caused by capacitive coupling or switch leakage, and it’s a quick job for a qualified electrician.
In Victoria, any work involving mains wiring, switches, or circuit modifications must be performed by a licensed electrician. Swapping a light bulb is DIY. Everything else on this list requires a professional.
More: LED Vs Halogen Downlights: What’s Best For Your Home?
Why LED Ghosting Is Common After a Halogen-to-LED Upgrade
Melbourne homeowners regularly upgrade from halogen downlights to LEDs for energy savings and longer lifespan. But many don’t realise that the existing dimmer switch, wiring configuration, and transformer all played a role in making the old halogen system work without issues.
Halogen bulbs draw 35 to 50 watts each. That high wattage meant any stray leakage current was insignificant relative to the total load. Swap those for 7-watt LEDs, and suddenly that same leakage current is a significant proportion of the load. The LED reacts to it. The halogen never did.
This is why ghosting often appears immediately after an upgrade. The wiring hasn’t changed. The switch hasn’t changed. But the bulb’s sensitivity to residual current has changed dramatically. Suburbs like Cheltenham, Hampton, Bentleigh, and Oakleigh, with large stocks of 1990s to 2000s homes that were built with halogen downlight circuits, see this frequently.
The fix is straightforward. Replace the old dimmer with an LED-rated dimmer, and if ghosting persists, install a bypass capacitor. A lighting upgrade done properly addresses the dimmer, the transformer (if applicable), and the bulbs in one visit.
After completing a lighting upgrade at a Melbourne home, the Byrd Electrical team received this feedback: “Professional, fantastic service!!! Great communication and reasonable price for both repairs and the rest of my wish list. Very clean and tidy. These guys have it all. Plus, turns out Ben is one of the BEST lighting designers in the business! Will only use Byrd Electrical from now on.” Theresa Dyer. Getting the dimmer, driver, and bulb combination right the first time is what prevents ghosting from appearing after the upgrade.
Areas We Service
We service homes across Melbourne and Bayside, including Brighton, Sandringham, Hampton, Beaumaris, Cheltenham, Mentone, Bentleigh, Elsternwick, Oakleigh, Malvern, Camberwell, Toorak, Glen Iris, Caulfield, Armadale, St Kilda, Elwood, Prahran, Moorabbin, Highett, Ormond, Carnegie, and surrounding suburbs.
Get the Ghosting Fixed Properly
If your LED lights won’t stop glowing and a bulb swap hasn’t solved it, call Byrd Electrical on (03) 9000 0666. Licensed electricians, 24/7 emergency response, on time or we pay you $200, and a 100+ year extended workmanship guarantee on all work. Electrician of the Year 2024 and 2025. We install, upgrade, and troubleshoot LED lighting across Melbourne and Bayside.
Frequently Asked Questions
Why do my LED lights glow after being turned off?
The most common cause is a small residual current reaching the bulb through an incompatible dimmer, an illuminated switch, or capacitive coupling in the wiring. LEDs are so efficient that even a tiny current produces a visible glow.
Is LED afterglow dangerous?
In most cases, no. The faint glow from stored energy in the LED driver is harmless and fades within minutes. However, if the glow is bright, persistent, or accompanied by buzzing or heat at the switch, have a licensed electrician inspect the circuit.
Why do LED lights glow on a dimmer switch?
Older dimmers designed for halogen bulbs leak a small current even in the off position. LEDs pick up that current and glow faintly. Replacing the dimmer with a trailing-edge, LED-compatible model stops the glow.
Can faulty wiring cause LED lights to glow when off?
Yes. An incorrectly connected neutral, degraded cable insulation, or wiring faults that allow current to leak across conductors can cause persistent LED ghosting. This requires a licensed electrician to diagnose and repair.
What is a bypass capacitor, and does it fix LED glow?
A bypass capacitor is a small component wired across the light fitting that absorbs residual leakage current before it reaches the LED. It’s the standard fix for ghosting caused by switch leakage or capacitive coupling, and one capacitor per circuit is usually enough.
Should I call an electrician for glowing LEDs?
Call an electrician if the glow persists after replacing the bulb, if it’s accompanied by buzzing or a warm switch, or if multiple fittings on the same circuit are affected. In Victoria, any work involving switches, dimmers, or circuit wiring must be done by a licensed electrician.
