computer chassis is energized

If I plug in the power cord to a desktop, which has nothing attached to it (no mouse, no keyboard, no monitor), and check the chassis with a electric neon light tester, the light comes on, indicating the chassis is energized. There is a tingling sensation if I touch the chassis. This happens even when the computer is not turned on.

I wonder if this is a power supply problem or motherboard problem.

do you have a multi meter?

The voltage is 0.5V.

Try a different outlet.
That one is ungrounded.

Mr.Scott said:

Try a different outlet.
That one is ungrounded.

Click to expand...

Or improperly grounded/wired. Probably a cheater wire between ground and neutral.

Mpegger said:

Or improperly grounded/wired. Probably a cheater wire between ground and neutral.

Click to expand...

Exactly.

By chance are you using a TV Tuner card or wired Ethernet?

If yes to wired Ethernet, is the router/modem from your ISP also connected to the in-home coax somehow?

After frying both the onboard Eithernet and it's replacement Network card at my mother's house, I finally figured out that the ground loop through the DSL modem (!) (that also was connected to a "set top box" tuner for the TV's ... via coax through the house) was basically murdering the NIC's.

Bonus for my sweaty hands always getting "tazed" even with the computer unplugged. Finally had to resort to using a wireless card in the computer and that works.

Still if you can try and get that fixed, it's an electrical hazard.

I changed the power cord to 3-prone one and the chassis is no longer energized. Still, I wonder if the chassis should be energized if the computer is not grounded.

Get a ups. They beep if not grounded correctly.

Well thats an awfully expensive test...

The ups I use doesn't do that. I'll shop one that does. Thanks for the info.

habbajabba said:

Get a ups. They beep if not grounded correctly.

Click to expand...

EarthDog said:

Well thats an awfully expensive test...

Click to expand...

I don't know if this will detect a joined neutral/ground, but it finds most outlet problems and is cheap:

https://www.homedepot.com/p/Commercial-Electric-Tools-Outlet-Tester-Green-MS112H/206029154

I have a similar model and it has been helpful to identify problems left over from the previous owners of our house and to verify I've fixed the problems.

torin3 said:

I don't know if this will detect a joined neutral/ground, but it finds most outlet problems and is cheap:

https://www.homedepot.com/p/Commercial-Electric-Tools-Outlet-Tester-Green-MS112H/206029154

I have a similar model and it has been helpful to identify problems left over from the previous owners of our house and to verify I've fixed the problems.

Click to expand...

It wont really show you a Grounded neutral (not that they really matter that much as they are tied together in your PNL anyway and you really should not have voltage on the neutral besides unbalanced loads) . At work before I can get a house inspected I have to do a Megger test (we are one of the few province's that require this ) . Puts out a High voltage (500-1000v) with no amps to check the insulation and is also a pretty fine ohm meter . But most DMMs would let you check for a Grounded neutral by checking continuity between the 2 .


@ op glad the proper cord fixed the problems . Those small tick testers are ok for a rough idea but they are not very accurate ( rub it on your shirt I bet it goes off ) . The one I use has a High and a low voltage indicator it but still is only ok .