Question If Surge Protectors Are Necessary Why Do We Use PSU?
Question If Surge Protectors Are Necessary Why Do We Use PSU?
I believe this is more of a marketing strategy than a solid technical fact. However, I’m curious about the details. I was looking for a socket with current protection to safeguard my computer against overvoltage. The "Lightning protection" statement felt like an exaggeration, suggesting it was just a promotional tactic. I’m not a Tesla enthusiast, but I’m certain no device can withstand lightning effects except the ground itself. "Lightning protection..." isn’t something I’d rely on.
If my goal was to shield against lightning, I would install a lightning protection antenna on my property and link it to the ground.
Secondly, I doubt surge protector sockets offer real assurance. There’s no definitive proof of their effectiveness, and holding manufacturers accountable isn’t practical. Additionally, the plug in my room is connected to both building and apartment insurance. In essence, it’s linked to two fuses in total, and in the event of high current, the circuit automatically shuts off electricity—this is standard procedure.
Thirdly, regarding voltage stability... If my UPS for the computer functions properly, it should continuously adjust voltage fluctuations. It must deliver electricity to the motherboard or CPU at an optimal level as required. Isn’t that the intended role of a power supply unit? And if a high-quality PSU can’t achieve this, why would I invest in it at all?
Let’s consider the path of electricity from the grid to the motherboard. Generally, electricity is generated at a central facility, grounded, and sent via a transformer in the local area. Major fuses are installed in neighborhood transformers to distribute power to homes, with additional fuses in individual residences. The electricity then travels through another fuse within the apartment before reaching the PSU. Finally, it is regulated by the PSU to supply components like the motherboard or CPU with stable voltage.
In this context, shouldn’t it be considered an overstatement to claim a surge protector is essential? If I’m mistaken, I’d appreciate the technical clarification.
Note
I’ve also encountered claims that surge protector sockets fail to protect devices or even cause damage. Some argue it might ignite fires, while others suggest that even with proper installation, replacement every 1 or 2 years is advisable to maintain protection. These conflicting opinions have led me to question its necessity. Nonetheless, I remain open to technical insights.
Concerning surge protectors, I’d like to share a response from one of our experts on this topic. The discussion about surge protectors began two replies prior to the link I provided (post #12). It’s worth noting that many people agree with Darbreeze on this matter. Surge protectors aren’t essential; a UPS with an AVR is a better choice. I personally use and currently rely on that setup. However, I can offer a strong explanation for why PCs need PSUs—power supplies transform AC from the mains into DC, which the computer parts require. Without a PSU converting AC to DC, none of the components inside the PC would function. In fact, PC parts don’t operate on AC power.
Yeah, I understand about AC and DC, but I didn't bring up that part. (I was talking about regulating voltage changes.)
Consider it more as a surge protector acting as a sacrificial component. Voltages that are slightly off can be corrected in various ways. Typically, they transform the excess power into heat.
Significant voltage spikes can harm equipment, making it preferable to damage the MOV in a surge protector rather than critical components like a costly voltage regulator. Most UPS and power supplies include MOVs, providing some protection even in these devices.
The issue remains that these MOVs can only handle a limited amount of power. They gradually degrade, and there’s no reliable method to assess their condition or performance.
In practice, you usually replace the surge protector after experiencing a major surge or periodically every few years to guard against frequent minor disturbances. It can feel misleading when purchasing, as it’s hard to verify if the device is still working properly.
The primary reason is that surge protectors are more affordable and simpler to swap out. They function in a way that can be damaging (as they are), yet you can easily replace them. Failing internal power supplies are often hard or not possible to replace.
BUT, if you're committed to ensuring power reaches your PC or other devices, a double conversion UPS is necessary. This unit maintains a steady output regardless of the input conditions.
In the event of a family member, their nearby transformer (located on a pole in an open area) carries a rating of 630A with a 240V AC supply. I’m certain of this after speaking with the repair team when they arrived to replace two overhead power cables that overheated and fell to the ground within less than 30 feet of me. A branch severed a tree nearby and fell onto the power lines, causing them to short together. A powerful discharge occurred, with two thick cables dropping sequentially before the 630A fuse tripped. Most fuses activate only when current exceeds more than double the normal level for a set period; at their rated capacity, they can endure up to 1000 hours. Circuit breakers generally trip 2 to 5 times the rated current before doing so. If your home uses 100A fuses or breakers, they won’t safeguard your computer.
I’ve experienced two lightning strikes close to my residence. On both occasions, connected devices failed. During the first incident, an Ethernet port on a laptop, along with the broadband router and a separate firewall, malfunctioned. The second strike caused similar failures in the router and firewall, plus a telephone answering machine to suffer scorch marks around its socket.
I currently have surge arrestors installed on TV antennas, + RJ45 Ethernet filters, but with the installation of fibre-to-the-premises broadband, that’s one less possible entry point. Neighbors reported TVs being destroyed and plaster cracking where underground wiring exploded. Little can be done against a direct or very close lightning strike, except for a Faraday cage.
My lightning strikes entered the house through underground mains cables, broadband coaxial lines, and copper telephone landlines. I would have recognized the damage if it had struck the TV antennas on the roof, since I was present during both strikes and didn’t lose any televisions.
As others have mentioned, if it isn’t an always-on dual conversion UPS, it may be offering minimal protection against mains fluctuations. Many UPS units only activate when the mains fails and the inverter starts, or they may include an AVR feature.
Some ATX power supplies already incorporate a MOV (Metal Oxide Varistor) to suppress mains spikes, along with Class-Y and Class-X capacitors to reduce internal RFI. There may also be an NTC (Negative Temperature Coefficient) thermistor in the power supply’s input to limit initial inrush current, which is then switched off by a relay in more advanced models.
Surge arrestor strips can lower the intensity of short-duration voltage spikes reaching your computer, but they won’t guard against prolonged blackouts, power interruptions, or other disturbances. Consider purchasing a surge arrestor strip if your local mains is particularly unstable—such as in areas with many air conditioning units or near factories with heavy machinery—but don’t expect it to resolve all issues.
When I worked as an EMC systems design engineer, we installed these filters (or similar solutions) on individual equipment housed in 19-inch racks. This approach is superior to using a simple MOV.