PC-Case conducts energy

[Deleted member 110184]

Hello there!

First of all, i am not an electrician and i am absolutely new to this. I have a Problem with my PC and am seeking for advice on how to handle it. I hope this is the right place to post this Thread, if not please let me now.

I just built a brand new Computer with all new components but i have the problem that my PC-Case conducts energy. This means as soon as i touch anything that is made of metal from the case i can feel the energy on my finger. It really is a constant shock and not just a short shock you would have with static electricity. First thing i did was to buy an outlet tester. I checked all the outlets for errors but all of them are all right.

I do have an UPS between the Outlet and my PC. So what i want to test now is if i plug out the energy from the Outlet and i run my PC only over my UPS, if i still get that shock. The Problem is, i really dont know how to measure the Voltage of the PC Case correctly. I do not know where i have to put the Voltage and the Ground Pin from the Multimeter to measure the Voltage of the case. Can anybody help me out with this??

Thanks!

 

[Fitzy]

Check the mounting of your motherboard, computer cases are earthed via the little mounting columns you screwed into the computer case before you mount the motherboard on top of these, makes sure that every mounting hole on your motherboard has one of these underneath and a screw is firmly tightened in every hole. If any of these columns are missing or the motherboard is not screwed down to them, it could cause your problem. Luckily you’re only working with 12v dc after the psu. Also check all the solder joints on the base of the motherboard to see if any are too long, especially on the capacitors legs etc, it’s not unknown for one of these to be just too long and just touch the case, therefore resulting in the occasional shock.

 

[DPG]

Definitely test the earth continuity (low Ohms range, power off!). Test it right from the earth pin on the mains plug to the case of the PC. Also test the voltage between a known earth (screw of the mains socket on the wall maybe) and the PC case whilst it is powered up. Try on both the AC and DC settings on your multimeter.

Let us know what results you get from these tests.

 

[Lucien Nunes]

The source of the voltage you can 'feel' is likely to be normal earth leakage that occurs inside the power supply unit, mainly due to the radio interference suppression components. These leak a small constant current that would normally pass down the ground lead back to the supply. If the ground lead is broken, the entire case of the computer loses its reference to earth potential and the leakage raises it to some arbitrary voltage between earth and 230V. The actual voltage is immaterial and although you can measure it, it is easier and safer at first to use the low resistance (e.g. 200 ohm) range on a multimeter to localise the break in the ground path from plug to power supply.

The problem will not be anything to do with the motherboard, all voltages there are too low to cause a noticeable shock under normal conditions and all are referenced to the case anyway; the case can't become live with respect to itself.

 

[wildwest]

Repeat.
The Suckit n See type Tester shown in does not verify neutral earth reversal.
OP describes himself as "new to this".
He also gives a good description of an AC touch voltage appearing on the case of his equipment.
He has asked how to measure what the touch voltage is.
He is new to this.
PLEASE DON'T advice him to carry out live testing with a multimeter

 

[wildwest]

The only advice should be get a competant person to check the socket.

 

[Lucien Nunes]

At this stage the socket outlet is not the prime suspect. The plug-in tester is not a thorough test, however it does indicate that something at earthy potential is connected to the earth terminal. Neutral, earth or anything near either of them is likely to remove the PC leakage current so even if there is a wiring error and no RCD, he would be unlikely to get a tingle. Using the principle of Ockham's razor (the simplest solution is likely to be correct) the fault probably lies in the ground connection to the PC PSU which can be checked easily first, and the socket investigated if the fault is not found here.

FWIW the OP is in Germany so the socket will be Schuko, non-polarised but with reliable side-contact earthing.

 

[DPG]

Repeat.
The Suckit n See type Tester shown in does not verify neutral earth reversal.
OP describes himself as "new to this".
He also gives a good description of an AC touch voltage appearing on the case of his equipment.
He has asked how to measure what the touch voltage is.
He is new to this.
PLEASE DON'T advice him to carry out live testing with a multimeter

He already has the pc powered up. It is very likely to be leakage current. The basic testing I have proposed exposes him to no more danger than he is exposed to already. I didn't advocate taking anything apart, or measuring at live terminals.

I am a big believer in safe working.

 

[wildwest]

On this one I don't mind being wrong.

 

[sham]

To me, I would see this as a fault to earth. I would get a electrician or some computer engineer to take a look.

 

[sham]

Your plug system is not earthed.

 

[DPG]

Your plug system is not earthed.

Impossible to say from info given.

 

[wildwest]

by experiment I can confirm, without an earth connection 107VAC on the case of my PC, neutral and earth swapped 0v on the case.
so I stand corrected.

 

[telectrix]

all PCs should be electrocuted...... oops thought thread was about politically correct.