Electricity in computer case

My computer is now completely assembled, most of my software is installed, and I’m working out the final few kinks.

One thing I noticed is that when I touch the back of the computer case, even if it’s off, I feel a slight tingle of electricity. Checking inside I can’t find any loose wires touching the edge. How can I solve this? I don’t want any electricity harming the electronics…or me.

BTW, the outlet is ungrounded, just like every outlet in Taiwan… :unamused:

Maybe your getting a little shock from where the motherboard is attached to the mounts. I’m creating a computer right now too and before I attach the motherboard to the mounts im gonna cover the mounts with a little bit of electrical tape.

Also check to see that none of the spare cables on the power supply is hitting the case and giving it power.

There was a thread about this topic a while ago. Here’s the link:

forumosa.com/taiwan/viewtopic.php?p=349153

I heard that you can connect the ground to a water pipe or something, and they even sell clamps that goes on the pipes for this purpose… the problem is how do I know its ground is working, and where do I get a tester?? or how do I measure the voltage or something? like I put one lead on the case and another where?? the floor?

Touch the case again. Not getting a shock anymore? It’s working!

If you’re getting a shock when it’s “off” try plugging it in the other way round - i.e. turn the plugtop around. (Your Live and Neutral are reversed)

In Taiwan, the water pipes are usually made of plastic, so this wouldn’t work.

Take the cover off of the wall outlet. (Pry off the cover using a small flat-bladed screwdriver.) Then look at the color of the wires. The black wire is “hot” and the white wire is ground. Then look at which side of the outlet the wires are connected to, and you can see which side is “hot” and which side is ground.

The wider hole (5/16 inch wide) is supposed to be ground and the narrower hole (1/4 inch wide) is supposed to be “hot”. However, in Taiwan, most electricians don’t follow this rule and wire the outlets either way.

Also, regarding the rule about standard wire colors, I’ve noticed that this is only true in new houses and buildings (less than about 10 or 15 years old). In old houses and buildings in Taiwan, the wires could be any color!

well in my building at least the incoming water pipes are metal, however it goes up to a water tower, so even if the pipe that eventually goes to ground isnt metal the water will still conduct electricity? so it would work as a valid ground?

I cant stick metal poles because I live on the 7th floor and that would be impossible!

[quote=“rahimiiii”]well in my building at least the incoming water pipes are metal, however it goes up to a water tower, so even if the pipe that eventually goes to ground isnt metal the water will still conduct electricity? so it would work as a valid ground?

I can’t stick metal poles because I live on the 7th floor and that would be impossible![/quote]

All water is ground. Fun Eh. If you dont like digging go get a UPS. Should cost about 1000nt at a 3c. Its a big battery that gives you a few minutes to turn off if you loose power. It also steadies and “ssmoothes” your power. 1000nt vs 65000nt for new computer = you do the math.

Most outlets are not grounded and I would not trust that the electrician used the correct colors. In fact for 110V outlets white should be neutral and red the life, while ground (if available) would then be black or green, depending on what cable has been used.

Very true.

Actually, these are the standard colors:

Black or Red = “hot”
White = “neutral”
Green = “ground”

The reason why “hot” can be either black or red is because the power that comes from the telephone poles into the house consists of opposite phases of 110 volts AC plus a neutral wire. So there’s 110 VAC between the black and the white wires and there’s also 110 VAC between the red and the white wires, and there’s 220 VAC between the black and the red wires. (The three wires going to the 220 VAC air conditioner outlets are black, red, and white.)

The difference between “neutral” and “ground” is that “neutral” is a wire that comes from the telephone poles (from the power company), but the “ground” wire (“earth” in British English) is supposed to be connected to a copper rod that is stuck in the ground right next to the building. (The “ground” wire does not come from the telephone poles.)

If the outlets have a “ground” wire, then the “neutral” wire and the “ground” wire are supposed to be shorted together at the fuse box. Therefore, you can use either the “neutral” (white) wire or the “ground” (green) wire to ground a computer case.

However, most buildings and houses in Taiwan don’t have a “ground” wire going to any of the outlets, and they don’t have a copper rod stuck in the ground near the building, either. But the “neutral” wire should be at the same electrical potential as “ground”.

If you can’t tell which wire is “hot” and which wire is “neutral” because of non-standard colors being used, then you can use a voltmeter, set to AC volts. When you stick one of the electrodes in one of the holes in the outlet and touch the other electrode to something concrete (like a wall for example), then if that side of the outlet is “hot”, you should see a small non-zero AC voltage. But if that side is “neutral”, then the meter should read zero volts.

[quote=“Mark Nagel”]Actually, these are the standard colors:

Black or Red = “hot”
White = “neutral”
Green = “ground”[/quote]
Well, not in Taiwan I guess - standard 3-core AC cable that you buy in a hardware store here has black, red and white leads only.

[quote]If the outlets have a “ground” wire, then the “neutral” wire and the “ground” wire are supposed to be shorted together at the fuse box.
Therefore, you can use either the “neutral” (white) wire or the “ground” (green) wire to ground a computer case. [/quote]
Taiwan uses the TT-System where Neutral and Ground should not be connected.