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I'm living in a house with electrical system without Ground wire and when I touch my PC case while standing on ground I get a zap from it which I believed are from suppression capacitor in PSU, I've tried to connect my PC case to the ground part of a TV coax cable which coming from the electrical pole outside and I doesn't get shock while touching my PC case anymore.

Is this is a good way for temporary grounded my PC?, it doesn't seem to have any interference on TV after I do this but I did worry about if there is a lightning strike the electrical pole outside then my PC might get damaged? (I know that lightning would go straight to earth and don't care about my PC but is it still potentially damage my PC?)

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  • \$\begingroup\$ It seems to be Grounding issue.check earthing \$\endgroup\$ – Umar Jan 10 '17 at 13:03
  • \$\begingroup\$ yes this is an external ground and diverse the line noise filter current to external ground which means the chassis is at the same potential as all other devices connected to gnd and now outside video gnd Considering antenna effects of all wires, this is safer and more immune. \$\endgroup\$ – Sunnyskyguy EE75 Jan 10 '17 at 13:08
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    \$\begingroup\$ It is said very often that lightning would go straight to earth but there have been a lot of lightning strokes not going straight to earth. May be nobody told them before where to go. ;-) Another common misconception is the believe that lightning strokes always takes the path of least resistance. \$\endgroup\$ – Uwe Jan 10 '17 at 14:42
  • \$\begingroup\$ Could you clarify "zap"? Is this a single-stroke static-like shock? Or is this more of a steady buzzzz? Repeatable currents to ground would worry me. \$\endgroup\$ – glen_geek Jan 10 '17 at 14:53
  • \$\begingroup\$ @glen_geek the zap are very strong when I'm standing with both of my legs on ground, I get it a lot of time while trying to plug USB in the dark but still haven't dead yet... when I connect the chassis to ground it did create some spark but after it get connected then everything is fine, if that zap are from Live then the wire would explode already, this house electrical system are quite old and they're using fuse and normal breaker without any GFI or something like that. \$\endgroup\$ – SandPox Jan 10 '17 at 14:59
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Static discharge to ground suggests that your house wiring ground circuit is ineffective (floating). Very old house power distribution was 2-wire.
Every PC has a three-wire power plug that expects to see a safe path to earth on its ground pin to protect you and internal static-sensitive electronics.
However, I would be reluctant to invite lightning into my home by a cobbled-up connection to ground. The term "ground" may ease your mind, but lightning has a way of not respecting the path you have provided for it.
The interconnection of devices to a PC is often complex, involving multiple devices, each of which is powered from the same AC source (monitor, amplified speakers, modem etc). I would plug all these devices into one power bar, and attach your grounding connection to that power bar only. Nevertheless, don't expect this grounding method to save your equipment from even nearby lightning strikes. Re-wiring your house might be a safer option - would it pass a fire-safety inspection?

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    \$\begingroup\$ He said his house doesn't have ground wire. \$\endgroup\$ – Rob Jan 10 '17 at 15:48
  • \$\begingroup\$ A direct hit vaporizes house wiring (little survives). How SandPox has grounded his equipment is safer than not. But relying on TV coax grounding is less than reliable. Even if TV is installed and maintained by SandPox, critters can chew through coax easily. \$\endgroup\$ – glen_geek Jan 10 '17 at 16:03
  • \$\begingroup\$ I don't even know if "fire-safety inspection" is a thing around here, but you're right, even I have a safe ground I made myself but if there is a lightning strike hit the power line then all appliances in my house would pretty much nailed so I just use the ground from coax cable to prevent some shocks when touching metal parts on my PC \$\endgroup\$ – SandPox Jan 11 '17 at 4:39
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Ungrounded outlets and mixed polarity plugs can actually be deadly. It would be possible to get full potential between two devices. This could burn up cables and devices alike. Incoming cold water pipes are another good ground point.

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    \$\begingroup\$ Though plastic cold water pipes aren't a lot of use for grounding. \$\endgroup\$ – Simon B Jan 10 '17 at 17:01
  • \$\begingroup\$ The incoming water pipes may be a good ground point only if they are made of metal with low resistivity and if they are plated with zinc instead of other eletrically isolating corrosion protection. \$\endgroup\$ – Uwe Jan 11 '17 at 11:29

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