Help me understand * I live in a house with older type electric installation without grounding in wall outlets (two wire type). Similar to: https://img1.etsystatic.com/053/0/7389273/il_214x170.749601009_d1oe.jpg * Power strip is connected to outlet. Nothing is connected to power strip itself. * Voltage detector screwdriver lights up when ground pin on power strip is touched! I have tried three different power strips over three different outlets. * When testing between ground and neutral on power strip multimeter shows 30 volts at first, but quickly drops to 9 volts. Again, there are no ground wire in electric outlet itself, where does this electricity "begin" then ? Also when PC is connected to power strip voltage detector lights up when certain PC case parts are touched like I/O backplate, PSU screws etc. I think electricity travels from power strip ground pin to PC case?
Do you have an ohmmeter and can measure your power strip(s) from neutral to the ground pin? In most countries I think, the ground is tied to neutral. But, this isn't supposed to happen until you go back to your electrical box for safety reasons. In your situation, it sounds like there is some leakage voltage from neutral to ground which would make your detector see some voltage, and that also makes it to your computer case since you said it's grounded. If your system not grounded...be careful with that OK?
Good idea testing power strip with ohmmeter! I did and there are no readings from neutral to ground (or 1 for that matter as in no contact). After trying different things I found what causes it! (though I am not sure exactly how). Apparently outlet socket/plug polarization matters in this case. If looking straight at the wall and phase line is on the right and plug is in "normal" position (cable downwards) then ground on power strip has voltage. If plug or socket is the other way around then no voltage is detected. Looks like electricity "jumps" and since there is no proper ground it "stays" here?? Now question is do I ignore it and keep it that way or turn this outlet upside down? Most sources I've red say polarisation does not matter for Schuko plugs and 2/3 of the continent use them (blue and red colors): https://upload.wikimedia.org/wikipe...ATE.png/1024px-Europe_PlugTypeInUseUPDATE.png In some countries where it is specified (like France) phase should be on right afaik. Currently I have connected it this way. But again, probably most of the continent has grounded outlets (I have one grounded outlet at home and no voltage can be detected on ground no matter which way plug is connected). Not electrified, because voltage is small, but yes certain parts of case (grounded ones I suspect) have positive voltage. Can this be harmful to PC or can I just happily ignore it?
I'd suppose that's simply due to you having a grounded power strip connected to a non-grounded outlet, because of what krusher_r said (voltage leakage from neutral or such). The fact switching polarity makes the voltage disappear would confirm this I think. Not sure but it's probably not good that your casing (=grounding) has voltage passing through it. Maybe it would be better to use a non-grounded power strip with a non-grounded outlet, if you can find one. The grounding serves no purpose anyway with a non-grounded outlet and at least you should get rid of the "case voltage" this way. Or just plug the PSU directly to the socket if you can.
1:buy a grounding rod 2/3 feet long with clamp 2:beat/drive grounding rod into earth 3:connect a wire from your neutral to said grounding rod 4:drink a beer...
Reading here https://www.reddit.com/r/HomeImprovement/comments/2vmdyz/ground_wire_has_current/ Sometimes the no contact voltage detectors can be activated by static electricity. If it's really dry where you are, and you're walking on carpet, etc., it might be picking up static.
After changing power strip from an old Trust Power Master 525U to Brennenstuhl 1159750015 ground voltage on PC case now reads 2V instead of 9V, so thats an improvement I guess lol
It's possible that there's a 'charge' on the ground lead when not connected The ground lead would 'drain' your system of any EMI and static/other charges if properly connected. All ground should be connected to each other in conventional household systems. When it is not connected you can measure something we call a 'Zwevende spanning' in Dutch. Literally translated, it's called 'floating voltage'. It might be you loose ground lead 'receiving' magnetic fields from the wiring next to it, thus creating a low voltage. This means nothing, the moment you connect something ( and thus putting a electrical load on to it ) the voltage will collapse. It is too weak for sustained current. So no worries, install a ground and it'll most likely be gone. You should, btw, it's not only safer, but it could make your equipment work better by removing unwanted interference. Just my 2c ^^
