LED light fixture glows when not turned on
It has been posted elsewhere, but there appear to be several reasons why LEDs can glow when the light is switched off. The underlying reason, of course, is that LEDs require very little power to illuminate. There is a video of someone standing under some transmissions lines and getting a LED to glow from the induced current.


The switch is not completely switching off; it is a dimmer or some other device that leaks some current when it is supposed to be off.
The switch is installed on the neutral wire. In this case, it isn't even necessary to have any leakage to earth. The cabling and circuitry acts as a capacitor that can have sufficient capacitance to allow a small current to flow.
There isn't a neutral wire. Though most countries have a neutral wire at near ground, there are some exceptions. Some old installations in Belgium and France have two hot wires. Hence (2) applies always.
If you have a dual-pole setup there are two live wires, one off at one end and one off at the other end. If the wire is long enough a current can be induced in the overlapping section of wire.