# DC power adapter leakage safety [duplicate]

Today while installing a 12v LED strip on my windows with the power adapter plugged but the LED turned off, I noticed the led that I pushed down against the wall got turned on partially. It wasn't right. My finger shouldn't have enough resistance to turn on those led with 12v. Right away, I tested the DC adapter output line with a 90-1000vac surveyor and found out that the 12vdc line from the DC adapter carries a high voltage AC. When testing with a meter, it measures about 12vdc, and unstable AC range from 38-0Vac. ( properly higher AC voltage, since my meter may not be fast enough.)

1, Is it safe to use this power adapter? ( It powers up the LED strip fine. I have also found a 5V usb charger that carries a HIGH voltage AC before, of which I discarded right away.)

2, What is the cause of this HIGH voltage AC? ( Is it because it's not isolated? or it's not filtered properly at the output end? I can't open the case, as it's sealed completely with no screws. )

## marked as duplicate by Andy aka, Olin Lathrop power-supply StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Aug 9 '17 at 11:02

• You should always disconnect the supply during the installation - errors such as drilling in the wrong place can have serious consequences... – Solar Mike Aug 9 '17 at 8:24
• "I can't open the case, as it's sealed completely with no screws." ahh, so naive... – dandavis Aug 9 '17 at 17:47