Slight shock from computer USB port

Cool Comps

Pirate Slayer
Guys!!!!!!!

Suddenly I realised yesterday my USB ports are giving me a slight shock if i touch them.
Now today i am getting the shock anywhere i touch the metal portions of the case!!
What should i do?
 

pimpom

Cyborg Agent
Check your earthing. In 99.9% of cases, this is not due to any defect in the system, but due to normal leakage in the PSU, UPS and spike guard.

The PSU etc have built-in filters against voltage spikes and EMI. These filters provide slight leakage paths to the cabinet metal which is supposed to be connected to ground. If the system is properly grounded, the leakage currents flow harmlessly to ground (earth) via the house wiring.

The problem is that the wiring in many buildings don't have proper earth lines. Therefore, when you touch any metallic part of the system, the leakage currents flow through your body and gives you a shock.

If your body is dry, the shock is mild and normally not dangerous. But if your body is damp, e.g. when you're sweating or if you've just finished having a bath, then your body's electrical resistance is much lower and the shock can be very unpleasant or even dangerous.

The solution is to have a properly grounded wiring.
 

Tarun

In the zone
^^^^^^+1 it earthing problem or check ur main CPU connector which is connected to ur mains and the PSU sometime it due to the wire ;)
 
OP
Cool Comps

Cool Comps

Pirate Slayer
BTW My Cabinet stands on a wooden platform. Can it be that the leakage isnt being transferred?

Also, I dont know whther its an earthing issue. But i found out that if i switch on the socket and then the UPS, a green led glows on my Mobo. And already there is shock on my case. Any further ideas. Yes ill be calling my electricin. However if he says that electric ports aare fine, will he be able to point out the problem or will i have to point it out myself(or call an engineer)
 

coderunknown

Retired Forum Mod
BTW My Cabinet stands on a wooden platform.

read pimpom's post once more. its about the earthing. not where your cabby is kept. it may happen if the earthing wire is broken to that particular socket or the earthing was not done properly when the electrical work was carried out.
 

casual_gamer

In the zone
In my case, if i touch the metallic portion wearing a slipper, i won't get any shock, but with bare foot i get shock. what does this mean? If it was a earthing problem i should get shock even while wearing slippers, right?
 

Faun

Wahahaha~!
Staff member
In my case, if i touch the metallic portion wearing a slipper, i won't get any shock, but with bare foot i get shock. what does this mean? If it was a earthing problem i should get shock even while wearing slippers, right?

Ever wonder why birds perching on high tension cables do not die out of shock ?

because they wear slippers made of dry/non-ionized air
 

guru_urug

iGoogle
@OP

Do this:
1) Try using another spikeguard and check if prob is gone
If you dont have another spikeguard then directly connect the PSU power cable to the wall socket, power on the CPU and check if there is still any voltage leakage (preferably with multimeter). If the problem is no more, then culprit is spikeguard, get a new one!
2) Incase there still is, then try using another wallsocket (preferably of another room. Check if the problem goes. If it does, culprit is the earthing in your room
3) If possible get another PSU from a friend and start your PC with it and check if the problem goes. If it does then culprit is PSU, get a new one!
If problem still persists then there is only one possibilty, the earthing in your house is faulty, call an electrician and get the problem fixed ASAP
 

pimpom

Cyborg Agent
This issue has come up several times before, so I prepared the drawing below a few years ago to illustrate how it works, but I never got around to uploading it until now. I hope it will help.

@casual_gamer: Look at the picture. See how the leakage current flows through your body and out to ground through your feet. If you're wearing rubber slippers, they block the flow of current. But this is only if your slippers are good electrical insulators and are dry.

leakage.png
 

s18000rpm

ಠ_ಠ
Do you have any Chinese or local make speaker system or similar stuff connected to your PC?

Remove all such connections and check.

I once had similar problem, only diff was my PC was transferring 240 volts to USB Ports, CRT monitor (shock on glass).
I thought there could have been earthing issue, our psu gone wrong, I checked up earthing, bought a new psu cooler master, but still got the shocks, then finally removed a local make 5.1 system connection, that bloody thing was leading current into the PC via 3.5mm cables.
 
OP
Cool Comps

Cool Comps

Pirate Slayer
The problem turned out to be with my spike buster. One of the earthing pins on it was loose so at times it was cutting off the earthing. My electrician told me that. I had another Spike buster(which i had bought from MD when i bought my rig but i hadnt used it). So i started using it. I also kept his tester. ANd There isnt any shock now.

BTW Can Your keyboard or mouse also shock you? Coz i feel a slight buzz in my fingers at times when using them. Now this can be my imagination or it can be since its quite late int he night. But just wanted to know.
 

pimpom

Cyborg Agent
BTW Can Your keyboard or mouse also shock you? Coz i feel a slight buzz in my fingers at times when using them. Now this can be my imagination or it can be since its quite late int he night. But just wanted to know.
Have you been having wet weather? Moisture on the mouse and keyboard can allow enough current to flow on them to give a slight tingling or buzz, especially if they are not perfectly clean. The accumulated dust and dirt absorbs moisture from the air. Even if the plastic surfaces look dry and reasonably clean, microscopic amounts of dust and moisture can get trapped there.

Also remember that no material is a perfect insulator. The plastic body of your keyboard and mouse can pass tiny amounts of current. Normally, such currents are too small to be felt. But they may be noticeable under certain conditions. Another factor is that different people have different levels of sensitivity.
 

jerrin_ss5

Never give up!!
very good explanation pimpom
i may sound naive but please help me as i am weak in electricals
but orange is ac and black i presume is ground so the leakage current should go through black wire na
 
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s18000rpm

ಠ_ಠ
Cool said:
BTW Can Your keyboard or mouse also shock you? Coz i feel a slight buzz in my fingers at times when using them. Now this can be my imagination or it can be since its quite late int he night. But just wanted to know.

That's earthing problem. Get the sockets checked again. Buy a Belkin spike buster.
 

rsk11584

Journeyman
most common assumption is earthing must be faulty first call electrician or take a multimeter and check earthing at socket if it is fine then something is wrong with the appliance, even in my house we have weird problem when the heater is swithched off sometimes in bathroom i get shock, called electrician and he checked earthing , heater etc and all is fine, now the shock is coming only morning during -6.30 to 07.00 am for some 10-15 mins not at all times so electrician told that someone must be using some faulty appliance, then had to tell neighbours about ti and guess the stupid neighbour stopped using his faulty appliance, probably an IRON ,,, but still electricity is hard to understand inspite of fauly appliance earthing should go via earth to ground and not shock the person,, dont know im not engineer tap in bathroom gave strong shock, and i am even today afraid but since electrician checked n certified strong earthing i need to only worry about neighbours, if the shock that ur getting is only sometimes and repeats only at specific times then it might be due to some faulty appliance used by somenoe in ur home
 

vamsi_krishna

Human Spambot
Brings back the memories of my old days. There were times, where, I was afraid to even go near my cabinet.

Anyway.. as the other members are pointing it out, it is clearly the grounding problem. Make sure that the socket is properly grounded. You will be good to go.
 
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