Wrong power cable in my LED light: still light when switched down off.

Flip the plug 180 degrees. ;)

One of my old lights retained power for about 15 mins after unplugged. Just one of them things. Shouldn't effect your grow if its only on for 10-15 mins after it's switched off.

that cable only acts as a medium for the power to travel, much like a road with cars or a pipe with water.... the electricity/cars/water in this analogy is the thing that is doing the action not the other way around. I use a digital timer and it works fine. don't have any light issues. maybe some of the capacitors are slowly leaking their charge? or just some LED defects, I'd trust numbers on anything light related they tend to know their way aorund a diaode if you know what I mean.

That's not caused by the power cord. Either your timer has a trickle or there's a slight defect in the diodes. I looked it up too long ago, but something about the phosphor layer glowing for long periiods of time after the power is cut. Not much you can do if it is a defective diode, but you can eliminate possibility of the timer causing it... plug it it directly, let it run long as necessary to have the glowing effect, then unplug it. if it continues to glow, it's not the type of power timer you are using (some cut power completely by cutting the circuit, others that don't can have a trickle of electrictity) if it remains glowing after you unplug it and no power timer inbetween, it's the diode/manufacturing. it can glow for a long time in some cases. that's a testament to the efficacy of the technology. I had a COB LED that had a glow for 15mins after power was cut. it was a cheap no-brand light off amazon.

Use a manual timer, it will cut power to the actual timer so the juice can't flow to the light at all.

ttps://www.rowse.co.uk/blog/post/why-do-my-led-lights-glow-after-being-turned-off

Led können auch nach dem ausschalte weiter leuchten da noch Strom in Kondensator ist schau mal hier