Unplugged computer sparked upon touching a cold heating pipe


First time here, so be kind with me, if this not the right forum to post.

I have (maybe) experienced an electrostatic discharge (ESD) from a computer case some days before, and I'd like to hear your opinions on this accident.

A computer case at my work, was not plugged in the mains outlet and it has been approximately 5 minutes, that it has been unplugged and switched off. Only thing plugged in, was the 2 monitors through their VGA cables and I think there were both switched off but unplugged. The computer was a 7+ years brand name machine, with a 300 W, 100 - 240 V, 50 - 60 Hz PSU.

Upon lifting the computer case with both hands to place it beside the desk, accidentally it made contact with the cold heating pipe passing nearby on the wall. Suddenly some yellow sparks with sound occurred (similar to arc welding sparks effect). The same time, the circuit breaker turned off the power at another room of the building.

According to my knowledge, I did not felt...

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1) The PVC coating is probably not designed to provide electrical insulation, so a cable fault could (unlikely, but could) make the pipe(s) live.

2) But mainly the cables will get too hot. The pipes are unlikely to get so hot that they actually damage the cables, but they will lift the ambient temperature for the cables so much that you'd have to de-rate them by a huge amount, or with the combined heat from the pipes and the heat from themselves they would be damaged. It's possible they should be derated anyway - how many are bunched, and how close, and for what length?

Suggest you move the cables, or lag the pipes. And even then get a min/max thermometer to check how hot it gets around the cables.

Finally, they shouldn't really pass through a cavity wall anyway, except in conduit, in case the cavity is ever filled with...

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Assemble the tools you'll need for soldering the pipe. Most importantly, you'll need a propane torch. This is a small propane tank with a regulator fitted on top; some have an automatic igniter, while others will require a striker to ignite the gas. You will also need lead-free solder (leaded solder can leach into your water supply, causing health problems). A tube cutter is the ideal tool for cutting copper pipes, but a hacksaw will also work. To clean the pipe, you will need some 120-grit emery cloth and a small can of tinning flux. All of these supplies can be purchased from a hardware store.


Cut the pipe at the desired location. Copper tubing is soft, and is best cut with a tube cutter. To use a tube cutter, tighten the tool around the pipe and then rotate it around, lowering the blade more with each turn. After several rotations, the pipe will break off cleanly. A hacksaw will also work, but it will leave a rougher edge that will make it harder to...

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Okay. Let’s talk about fixing water lines. Depending on what region of the country you’re in, you may see PEX tubing, which is a type of plastic or something, but in the five boroughs of New York City it is exclusively copper. If it’s not, you’re not legal. So this is what we call half-inch, indicating the size of the pipe, half-inch type L. L is the indicator of whether you can use it for potable water, potable being clean, domestic drinking water, showering water. Okay. This is what you see throughout the city, under your sinks, everything else. This is a fairly thick-walled copper pipe, and it’s easy to repair unless you have something bad happen.

But generally speaking it’s easy to repair. Now for the purpose of this video I’m going to show you how to solder a 90, okay, also known as an L, which is a very small fitting. This would be, for example, let’s say we installed a new vanity or a kitchen cabinet. You’d have a raw copper pipe coming out like so. All right. And...

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Testing the Temperature
Quite a few people have commented that I used way too much thermal grease (compound) and that the amount I used would cause overheating. I disagree with this view. So in an attempt to provide some kind of proof, one way or the other, I decided to monitor the temperature for a few weeks with SpeedFan v4.44. Then to take the laptop apart again, clean it up, using the suggested alcohol wipes method, and replace the thermal compound. This time I would use a thin amount. I would than assemble everything and then monitor the temperature again. I followed the same process as before with the slight suggested changes. This documents that process.

According to the CPU chip specifications for a LF80537 T5500, which is a Intel Core 2 Duo Mobile, the Minimum/Maximum operating temperature (°C) is 0 - 100°C. The maximum operating temperature of the CPU was 65°C before I started this process. After I completed the process the maximum operating temperature was...

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topic 30479

A discussion started in 2004 & continuing through 2017

Q. I am a civil engineer trying to figure out the following problem for a high-end home builder. After just finishing this exclusive house, the owner started complaining about blue water in their domestic water system. The local water authority was contacted and confirmed through water sample analysis that it was copper corrosion, and happening only at the referenced house. Suspecting potential electrolysis due to improper grounding of the electric wiring, an independent electrician was hired and confirmed that grounding was correct. Further inspection revealed that the copper piping from the hot water heater was connected to galvanized steel reducers and the connection was corroding and starting to leak. Does that explain the blue/green water in the system? Both the hot and cold water had the coloring, with the cold water having more pronounced evidence of the bluish tint! Due to the size of the house, the...

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