Protecting the PC from power surges & spikes

dor_13

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Oct 26, 2011
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Hi,

I had a PC with mainly the following components:

  • ■ Motherboard Asus P7H55-M PRO
    ■ RAM KINGSTON 2GB/1333MHz
    ■ HDD WD 500GB, 7200RPM
    ■ Graphic Card GV-R575D5-1G
    ■ Chassis HEC 7328
    ■ Power Supply HEC 550TE
    ■ CPU Intel Core i5-750 2.66 8M LGA115
Why did I wrote "had" you ask? Because one day, after 3+ years of using this PC, a big spark was coming from the PSU when trying to turn on the power switch near the power socket.
By a lot of testing I found out that the PSU is totally damaged and also the motherboard. I'm not sure about the other parts (like HDDs... which I hope they are still OK).

So now, after learning my lesson, I'm buying a new PC with protection from power surges & spikes that could be made by the air conditioner, since that my air conditioner is probably the cause for the power surge.

Only thing is that I don't know of which protection to buy and which component is considered a quality power surge/spike protector.
I've read about Metal oxide varistor (MOV) and UPS, but not sure which one of them is sufficient to protect from the power surges/spikes made by the air conditioner (which is connected to the same single power outlet with my PC).

Please help me on this with some examples of recommended UPS/MOV.
Also please write the configuration by which to connect the PC and UPS/MOV and air conditioner to the single power socket outlet (should I connect the MOV to the power outlet, and the UPS to the MOV, and then the PC to the UPS?)

Thank you!

Edit #1:

I draw a picture of the current power configuration:



I've named each single power socket outlet (prefixed with 'U') and each multi-socket (prefixed 'M').
'M1' is connected to the single power outlet that's on the wall.
 
Solution
Don't put the computer stuff on the same outlet as the air conditioner!

As far as UPS etc? I have a couple of APC UPSs, and a couple of industrial strength surge suppressors.

What kind of surge protector or UPS would you suggest?
I've edit my post and added a picture to show my current configuration.
 

But I don't have anywhere else to put it :/
I have a total of 3 single wall power socket outlets in my room.
One of them is for PC stuff and air conditioner.
The second one is for PLC (Power line communication).
The third one is close to my bed and I don't want the electricity radiating near my head, so nothing can be connected to it :s
 


+1

Seriously they are in your walls. The magnetic fields are not going to hurt you. The voltage is 120/240 V so very low. I work with 69-500 kV. You are in more danger from sun light and you still go outside.
 



Hey guys,

I understand what you're saying and mostly agree with it.
Though, the magnetic fields aren't what I'm worried from, but from the electric fields.
As far as I understand, the wires are like antenna and:

  • ■ with bigger demand of current by the load = high magnitude
    ■ with varying load consumption ("spikes of current") = high frequency
It makes the antenna to radiate like a radio transmitter station :ouch:

Of course, whatever I described is just to illustrate why this situation is bad, means I'm not sure of the magnitude of the radiation because that I'm not a professional electronics engineer.

I think that the wires don't go near my head because of the design of the house (there aren't any power outlets in that area and nor any efficient path to other rooms in the house, it's better to pass the wires from somewhere else.)

But obviously I'll take your advice and try to connect the air conditioner and PC stuff to different power outlets. :)
 


Well I am currently in my fourth year as both a electrical and computer engineer. I also am working for a very large power engineering company as a co-op.

The difference between an electric and magnetic field is the movement of the charge. A charge at rest gives off an electric field. When that charge and its field start to move then it also has a magnetic field such as the power running through your walls. Almost everything has a electric and magnetic field. Even you have one.

On the issue of the current going through your room there is two responses why that is a non-issue. First, your room is limited in the amount of current it can draw by the fuse in your main breaker. Most bedrooms have a 20A breaker. So you cannot have more than 20A going through your room at one time. An example of this is when you plug in to many high current appliances and your power goes out in that room. The circuit was tripped and you have to go and switch it back on. 20A is very low. Once again the power that I deal with is in the kA. Second, your room is wired up in series. This means that the current going through one outlet will be the same across them all. If you pull 20A in one outlet then it will be going through your entire room. This is to protect the wire in the walls which are only rated to a certain current before they heat up too much and burn. Not something you want to happen. Each of your rooms are in parallel with each other. Here is a very simple drawing I did in paint. I would make a better one in AutoCad but it seems that my update to 8.1 has messed up the install.
GdCqZTA.jpg


And on to your second point about the frequency of the power. Power is transmitted as AC (Alternating Current) and it comes into your house as AC. It even comes out of your power outlets as AC. It is only converted to DC (Direct Current) when you have a power adapter (power brick for laptop, PSU, etc.). This means that the frequency of the power being transmitted is fixed and does not change. In the US it is 60 Hz (60 cycles per second) or 50 Hz in Europe. This is why you cannot used a device bought in America in Europe without a special converter. The device is designed to use 60 Hz and not 50 Hz. It will destroy the device. So there may be times when there is a spike in current because of a faulty grid but the frequency of the wave will remain the same.

Now on to your radio transmitter. These use electromagnetism to send out wave that can be picked up by receivers. The power levels are so low and the frequency is also so small that there is little to no power be transmitted into you. And if you have power outlets around your room the most likely you have a power cable going around your room as well as you can see in the picture I drew the all have to be connected to each other.

Hope this helps and ask more questions if you still do not understand something and I will try to help.
 
I think I got it: the radiation magnitude of 20A @ 230VAC is small and also mostly creates a magnetic field (not dangerous), not an electric field (is dangerous but small in our case).
 


No no no. Neither are dangerous in your case. You cannot have a magnetic field without a electric field. They can both be dangerous at very high levels but in your case they are not.
 
Question for the OP:
Do you frequent a coffee shop with WiFi?
Do you use a mobile or cordless phone?
Do you use a wireless mouse or keyboard?
Have you ever taken a trip by airplane?
Do you sit near the PC or monitor when it is on?
When you plug something in, are you holding the plug?

Do you go outside?

If the answer to any of those (and more) is yes....the radiation is already streaming through you.
 

OK. Thank you :) I guess I have a lot to learn.

My answers are colored with blue.

The thing is that the single power outlet that sources all the PC stuff has relatively a lot of power coming out of it. But as you said it's not radiating a mass of energy so I suppose it's OK :]

I just think that it's a good habit to avoid things that radiate.
And my imagination of the amplitude to frequency plot of the current drawn from the power outlet makes me think of it as radiating badly..