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I was installing new LED lamps on my kitchen, which seemed to be functioning well. After turning off the lights, the newly installed lamps still had a dim light, that kept itself for quite long.
I've measured around 60VAC on the OFF switch for these lamps and 110VAC for the OFF switch attached to another lamp.
After lots of head scratching, I've tried to plug just one leg of the LED lamp into a plug hole, result on the picture below.
Why does this happen? How can I prevent it? Does it take a toll on my electrical bill?