Question PC case conducting electricity?

Jul 14, 2019
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Hey all! So yesterday I finally finished my first pc build after literally 3 days of blood, sweat and tears. Before putting on the side panels, I decided to test boot it to make sure everything was in order, and sure enough it was, installed windows, all parts were detected, things were smooth as butter.

Great I thought. Now I just need to tuck away some cables and put on the side panels, easy enough. Went easy enough, zip tied some cables and closed the case. Boom. Done, I thought. Now, before starting my build I'd been watching hours of guides and had read countless of forum posts about common rookie mistakes and dumb mistakes people made on their first build to prepare myself for any dumb mistakes I might've done. One those rookie mistakes I made sure to check for was to make sure the case was NOT conducting electricity. So after mounting the sidepanels, I grabbed a current checker and tested the case for any current between it and the radiator in my room whilst the PC was plugged in. At first, it came back fine, I prodded the top of the case, the side panels, the back, no current at all. However, after a couple of prods I figured the case is painted, so it might not be conducting electricity on the outside. So I prodded the thumb screws on the back of the case, and sure enough, it came back like this. Now, I could only test the thumb screws on the back of the case since they were the only non-coated metallic part sticking out on the outside of the case.

Now things are about to get even weirder. After som more prodding and making sure the thing actually is showing current between the case and the radiator, I unplugged the PSU and switched it off on the back. But guess what? The thin is STILL CONDUCTING ELECTRICITY!!! How, you may ask. Well since there was only one cable plugged in, the HDMI, it had to be through that one. Keep in mind the HDMI was actually connected to a screen, which was connected to a power outlet in the wall. So anyways after unplugging the HDMI it stopped.

If you thought things couldn't get weirder though, it's about to. So after seeing all this I decided to pull out my old desktop pc and plug it into the EXACT same outlet, with the exact same power cable, screen and HDMI cable. And that too showed up as conducting electricity. and this case had way more unpainted metal, and ALL OF IT including the screws showed up as having a current!! So at this point I have absolutely no clue what's going on.

Things I've checked / had suggested: The MOBO touching the case: I find that very unlikely, considering I paid extra attention to making sure ALL standoffs were in, and that there were NO rogue standoffs sticking up from the case and poking the motherboard in the back. I even screwed in the MOBO and removed it again to double check that all the standoffs were correctly placed, and then triple checked from the back of the case to make sure all the threads sticking out lined up with the screws on the front of the mobo. I had read about people frying their shit from rogue standoffs / not having all standoffs in so I made sure to the best of my ability that they were all in. Also unlikely since the other PC that's been running for 8 years has the same " problem ".

Well that's about it lol.

Also some things to keep in mind: The power outlets in my room are NOT grounded. Our house is old. The radiator is grounded I think, but I'm not sure. I just tested the old PC after having it showing current between the radiator and the case and it seems to be working fine. I don't want to risk anything with the new PC though, I don't have the money to fuck this up lol.

Appreciate any and ALL responses! :)

EDIT: TL;DR Both my new and old PCs seem to be conducting electricity from the case to the radiator: View: https://imgur.com/gallery/alfuywO
. Power outlets not grounded, not sure about radiator. Still conducts electricity even without the PSU plugged in, just an HDMI cable. Help pls.

Update: So i managed to find myself a long ass extension cord and plugged my pc into a grounded power outlet thru that. Now the case is not showing any current when pegged with the tester to the radiator. I have no idea what’s going on. I can’t keep it in the grounded outlet though because it’s running right across our hallway :S
 
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Jul 14, 2019
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My guess is that that current you were reading was a bit of static charge buildup that you were discharging through your meter, since your computer was not grounded before. Also, I bet that the case, like the chassis of a car, is used as the common ground, so, when you plugged your PSU into ground, your case became grounded, same as the radiator, and therefore at the same charge, therefore no current.

You do have to be careful about static charge and computers, as I'm sure you're aware, be careful when working on the inside of that case, if your body ends up charged differently than the case, and you touch something in there that isn't the case, there might be a shock and something might break, so, for now, just touch the case periodically to even out the charge.
 
Jul 14, 2019
2
0
10
0
My guess is that that current you were reading was a bit of static charge buildup that you were discharging through your meter, since your computer was not grounded before. Also, I bet that the case, like the chassis of a car, is used as the common ground, so, when you plugged your PSU into ground, your case became grounded, same as the radiator, and therefore at the same charge, therefore no current.

You do have to be careful about static charge and computers, as I'm sure you're aware, be careful when working on the inside of that case, if your body ends up charged differently than the case, and you touch something in there that isn't the case, there might be a shock and something might break, so, for now, just touch the case periodically to even out the charge.
Hey!
Yeah it seems like the issue went away when I plugged my PC into a grounded power outlet. My other power outlets aren't grounded and that seems to be where the problem occurred.
 

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