why does the psu need to be on while grounding yourself

Unknown6

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Jun 12, 2014
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I am doing an assignment on internal hardware components and I cant find an answer to this question!
How do you ground yourself and why does the P.S.U need to be on.
 
Solution
Working on a powered on computer is generally a bad idea. While you shouldn't get a shock if it's correctly earthed (and aren't in the PSU), you can still cause component damage if you short something.

If you have switches on the power sockets, then you can plug the PSU in but leave it switched off, which means that there's ground and neutral but no power. But make certain that it's in the off position.

Generally you're fine without doing anything more than just making sure to handle stuff without shuffling around on carpet and making sure that you're touching something on the ground plane (e.g. connector) of the component before doing anything to it.
Working on a powered on computer is generally a bad idea. While you shouldn't get a shock if it's correctly earthed (and aren't in the PSU), you can still cause component damage if you short something.

If you have switches on the power sockets, then you can plug the PSU in but leave it switched off, which means that there's ground and neutral but no power. But make certain that it's in the off position.

Generally you're fine without doing anything more than just making sure to handle stuff without shuffling around on carpet and making sure that you're touching something on the ground plane (e.g. connector) of the component before doing anything to it.
 
Solution


Wrong . This can cause lethal accidents . It also cannot help prevent static discharge . The impedance of the earth is far too high

Less likely in the US , but in much of the rest of the world where the earth and neutral wires are joined its a very bad idea
 
Again, doubt it. Static electricity has incredibly tiny amounts of charge, the issue with electronics is simply that when it equalises it tends to have massive amounts of voltage and thus creates relatively high currents for a short amount of time. A moderately high impedance (but certainly still lower than that of your body) slows discharge.

Also, I'm in NZ where we do join earth and neutral. There's a big earth stick out the back.
 


The static is not a danger to anyone .
Yes it might fry RAM , Graphics RAM and possibly other components

But if there is an electrical fault in your house you and and the earth you have created become the direct current path ... and you die .
This is incredibly easy to avoid . Dont work on your pc when it is plugged in .

That big pipe hammered in to the ground as your houses earth has so much resistance there is no way that that can protect your pc components from a static discharge .
So there are NO advantages of working with the psu plugged in and a potentially huge downside
 


Yes , because you die when you try to work on your plugged in computer
 
Excuse me? I've worked on lots of stuff unplugged but with phase off - no power means no danger.

Even worked on stuff live - so long as you stay away from the live bits you're fine.

Just saying, if phase and ground are swapped, touching e.g. the ports on the back or the end of any shielded cable (e.g. VGA, DVI, headphones, USB) would be as bad as touching any of the innards.
 
Touching your case equalises you and the case, which is enough to prevent static shock between you and the case (assuming your clothing is at least vaguely conductive e.g. wool, cotton. Synthetic materials tend to be even better insulators, and thus are easier to build up charge on).

In general, if you have everything at the same potential, it does not matter if that potential is the same as ground. Ground makes it easier if you need to grab extra stuff later, though.
 


There is only a small chance of a lethal accident when working on a pc that is plugged in . It would usually require a fault in the houses wiring . An experienced professional can definitely minimise the risk .

But advising a young person who has no electronics or power experience to handle a computer while it is plugged in is unwise .
More so when nothing is achieved by having it plugged in .

 


And if there is a fault in the houses wiring, or in the wiring of your new power supply, that will still kill you .

You do not need to try and earth the case to work on a computer . You need to reduce or eliminate the potential between you and the case .
You can do that with an earth strap connected to the case , or just by touching the case before you pick up components .The case does not need to be connected to anything .
So , while the risk of plugging the pc in is small it also has no benefit , and should be avoided

 
As I said, it would need to be a very specific fault in your house's wiring, and that fault would affect you whether or not your PC was open. Touching the case while it was closed would have exactly the same effect.

Also, electric shocks are not necessarily fatal.

But yes, there's little benefit to plugging it in.