EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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It can be unsettling to see your LED lights emitting a faint, ghostly glow even after you have flipped the wall switch to the “off” position. This phenomenon, often called “afterglow,” is usually not a sign that your home is haunted—it is an electrical side effect of how energy-efficient LEDs interact with modern switch systems.
Because LEDs require very little power to illuminate, they can capture stray currents that would never even make an incandescent bulb flicker.
Many older dimmer switches were designed for incandescent bulbs, which require a high electrical load to work. These switches often have a “leakage” current that remains even when the switch is set to off.
The Cause: This small amount of electricity is enough to charge the capacitor inside an LED driver, causing it to emit light.
The Fix: Ensure you are using a “LED-compatible” or “C·L” dimmer switch. These are specifically engineered to cut off power completely and prevent leakage current from reaching the bulb.
If your light switch has a tiny neon or LED indicator light to help you find it in the dark, that little light is part of the problem.
The Mechanism: To keep that indicator light powered, the switch allows a tiny, constant flow of electricity to pass through the circuit—even when the main light is turned off. LEDs “steal” this tiny amount of current to glow, whereas old-fashioned incandescent bulbs simply couldn’t light up with such little power.
If you have multiple wires running through the same conduit or cable bundle, the electromagnetic field from a “live” wire can induce a small amount of voltage into a “dead” wire.
The Result: This is known as “ghost” or “induced” voltage. While it is rarely enough to power an appliance, it is enough to make a high-efficiency LED bulb glow faintly. This is common in homes with complex, long-run wiring configurations.
Not all LED bulbs are created equal. Some lower-quality bulbs lack the internal circuitry needed to fully “drain” their capacitors when the power is cut.
The Reality: A high-quality LED has internal components that prevent stray current from reaching the diode. If you have a mixture of bulbs and only one is glowing, the issue is likely the bulb’s internal architecture rather than your home’s wiring.
In most cases, a faint glow is an annoyance rather than a safety hazard. However, there are two exceptions:
The “Flickering” Warning: If the bulb isn’t just glowing, but strobing or flashing, you have an unstable circuit or a failing switch that could eventually lead to arcing.
Compatibility Heat: If the glow is accompanied by a buzzing sound or the switch feels warm, you have a compatibility issue that is putting unnecessary stress on your home’s electrical wiring.
As a master electrician, I frequently see this issue in “smart home” setups. Many smart switches require a “neutral” wire to operate, but if they are installed in a house that lacks one at the switch box, they often “bleed” a tiny amount of current through the light fixture to power themselves. This is exactly why your lights glow. If you are installing smart switches, always check if your electrical box has a white neutral wire. If it doesn’t, ensure you buy “no-neutral required” smart switches specifically designed to work without creating that pesky afterglow.
Are you noticing any of these brighter lights flickering or humming, or is the brightness constant? Call us at 416-838-9006 or visit our contact page — we will be happy to help.
Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp
