Question If Surge Protectors Are Necessary Why Do We Use PSU?

Jan 22, 2025
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Yes, I think this is a bit of a marketing ploy. But I'm not sure and would love to know the technical answers. I was searching for a socket with current protection to protect my computer from overvoltage. But the "Protects from lightning" claim seemed exaggerated to me and made me think it was a marketing tactic. I am no Tesla, but I am sure there is nothing on earth that can tolerate lightning except the ground. "Protects from lightning...." Isn't that <Mod Edit>? If I wanted to be protected from lightning, I would install a lightning protection antenna on my building and connect it to the ground. (Lightning rod)

Secondly, I don't think surge protector sockets can really guarantee this. Because there is no way to prove otherwise and you can't blame the manufacturer for it. Also, the plug in my room is connected to the building and apartment insurance. In other words, it is connected to two fuses in total, and in case of high current, the electricity is automatically cut off... This is a standard.

Third the voltage problem... If my UPS on the computer is good, it should already be constantly regulating voltage fluctuations. It should send the electricity to the motherboard or CPU at the ideal level as needed. Isn't that the purpose of a PSU anyway? And if a quality PSU can't do that, why am I paying so much for it?

Now let's think about the journey of electricity from the power grid to the motherboard... Roughly speaking, electricity is generated in the main distribution facility and is grounded and sent to a transformer in the local area. Large fuses are used in the main transformer in the neighborhood to send electricity to the houses, and there is another fuse in the houses. In addition, the electricity passing through this fuse also passes through another fuse within the apartment. Finally, it is sent to the PSU, and the PSU regulates the voltage to power components such as the motherboard or CPU HDD. What I mean is that the components inside the computer go through certain protection stages before being supplied with electricity.

In this case, isn't it an exaggeration to claim that a surge protector is absolutely necessary? If I am wrong please I want to know the technical answer.

NOTE
I have also come across some claims that surge protector sockets do not work their devices and damage them. There are those who say that it can even cause a fire, and there are those who say that even if everything is fine and necessary, it should be replaced every 1 or 2 years to guarantee surge protection. In short, these contradictory claims, when taken together, led me to believe that it was unnecessary. But I could be wrong, and I'm technically open to persuasion.
 
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Regarding surge protectors, i need to link a reply of one of our resident experts regarding this,
link: https://forums.tomshardware.com/threads/everything-work-but-it-doesnt-work.3773133/#post-22771910

A long read, but i agree with Darbreeze about surge protectors. Talks about surge protectors start two replies before the one i linked (since reply #12).

If Surge Protectors Are Necessary Why Do We Use PSU?
Surge protectors aren't necessary. Better to get UPS with AVR in it. (Like i did and am currently using.)

But i'll give you stellar reason why do we (PCs) use PSUs;
PSUs convert the AC from the mains, into DC, that PC components use.

Without PSU and it converting AC to DC, none of the components inside the PC will work. PC components do not work on AC.
 
Regarding surge protectors, i need to link a reply of one of our resident experts regarding this,
link: https://forums.tomshardware.com/threads/everything-work-but-it-doesnt-work.3773133/#post-22771910

A long read, but i agree with Darbreeze about surge protectors. Talks about surge protectors start two replies before the one i linked (since reply #12).


Surge protectors aren't necessary. Better to get UPS with AVR in it. (Like i did and am currently using.)

But i'll give you stellar reason why do we (PCs) use PSUs;
PSUs convert the AC from the mains, into DC, that PC components use.

Without PSU and it converting AC to DC, none of the components inside the PC will work. PC components do not work on AC.

Yeah, I know about AC and DC, I didn't mention that aspect. (I mentioned that it regulates voltage fluctuations.)
 
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Regarding surge protectors, i need to link a reply of one of our resident experts regarding this,
link: https://forums.tomshardware.com/threads/everything-work-but-it-doesnt-work.3773133/#post-22771910

A long read, but i agree with Darbreeze about surge protectors. Talks about surge protectors start two replies before the one i linked (since reply #12).


Surge protectors aren't necessary. Better to get UPS with AVR in it. (Like i did and am currently using.)

But i'll give you stellar reason why do we (PCs) use PSUs;
PSUs convert the AC from the mains, into DC, that PC components use.

Without PSU and it converting AC to DC, none of the components inside the PC will work. PC components do not work on AC.
Bridge rectifier does. LoL
 
Think of it more as a surge protector is a sacrificial part. Voltages that are just a small bit off there are a number of ways to correct that. Mostly they convert the extra power to heat

Very large voltage increases will damage stuff so it is better to have the MOV damaged in a surge protector than some part of your power supply like a expensive voltage regulator. Most UPS and power supplies also contain MOV so there is some power protection even in those units. The problem is these MOV devices only can absorb so much power. They in effect wear out and there is no way to really test and tell if they are good or not.

Pretty much you use a surge protector and you just replace it when you think you had a large surge or you just replace them every few years just in case you had a bunch of very small power surges. It is almost a scam when you buy something and can not tell if it is still functional.
 
But the "Protects from lightning" claim seemed exaggerated to me and made me think it was a marketing tactic.
The main reason is that surge protectors are cheaper and more easily replaced. They can do their job in a destructive manner (as they do) and you can replace them with very little effort. Internal power supplies that fail are difficult or impossible to replace.
BUT, if you are serious about the power going into your PC (or other electronics), you will use a double conversion UPS. That device generates constant output no matter the input (or lack of it).
 
Large fuses are used in the main transformer in the neighborhood
In the case of a family member, their local transformer fuse (on a pole in a field) is rated at 630A (240V AC supply). I know this because I asked the repair crew when they came out to replace two overhead power cables that melted and dropped to the ground less than 30ft away from me. Quite spectacular. A branch broke off a tree in a wood nearby and dropped on the line and neutral wires, shorting them together. Big flash from the pole, two heavy wires fell to the ground, one after the other. Finally the 630A fuse blew, but only after both cables came down.

Most fuses only blow when more than double the current flows continuously for a pre-determined time. At rated current, they may last for 1000 hours. Circuit breakers typically take 2x to 5x the rated current before tripping. If your house is protected by 100A fuses or breakers, they're not going to protect your computer.

I am sure there is nothing on earth that can tolerate lightning except the ground.
I've had two lightning strikes near my house. On both occasions, things attached to the LAN died. In the first instance the Ethernet port failed in a laptop, plus the broadband router and a separate hardware firewall died. On the second strike, similar failures in router and firewall, plus a telephone answering machine died with scorch marks around the telephone landline socket.

I have surge arrestors connected on TV aerials, + RJ45 Ethernet filters, but now I have fibre to the premises broadband, so that's one less potential entry point. People in the neighbourhood had their TVs blown off the wall and cracked plaster where buried mains wiring exploded. Nothing much protects from a direct or very close lightning strike, apart from a Faraday cage.

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My lightning strikes entered the house via underground mains cables, broadband coax and copper telephone landline. I would have known if they'd hit the TV aerials on the roof because I was present for both strikes and I didn't lose any TVs.

If my UPS on the computer is good, it should already be constantly regulating voltage fluctuations.
As others have said, if it isn't an always online double conversion UPS, it may be doing very little to filter the mains supply. Many UPS just kick in when the mains fails and the inverter starts up. Others may include an AVR facility.

Finally, it is sent to the PSU,
Some ATX PSUs already contain an MOV (Metal Oxide Varistor) to clamp mains spikes, plus Class-Y and Class-X capacitors to reduce RFI generated inside the PSU. There may also be an NTC (Negative Temperature Coefficient) Thermistor in the PSU's line input to limit the initial inrush current, then switched out by a relay in better designs.

Surge arrestor strips can reduce the level of short duration voltage spikes reaching your computer, but they won't protect against long term brown outs, power cuts and various other disturbances. Buy a surge arrestor strip if your local mains is particularly "dirty", e.g. if your building is full of air conditioning units or close to a factory with heavy machinery, but don't expect it to cure everything.

When I worked as an EMC systems design engineer, we fitted these filters to individual items of equipment in 19in racks. Better than a simple MOV.

Schaffner_FN2060_10_06_View2_20181019115326.jpg
 
I've had two lightning strikes near my house. On both occasions, things attached to the LAN died. In the first instance the Ethernet port failed in a laptop, plus the broadband router and a separate hardware firewall died. On the second strike, similar failures in router and firewall, plus a telephone answering machine died with scorch marks around the telephone landline socket.
I had similar. But only specific parts died.
Ethernet port, HDMI port, etc.
The overall devices were mostly OK.

But a couple of very weird 'other things'.