Short answer: protections shut the power supply down when something goes wrong, before damage can spread to your other parts. A good unit has all the main ones. Lab reviews also check how tightly they’re set, which matters just as much.
The main protections
| Short name | Full name | What it does |
|---|---|---|
| OCP | Over-current protection | Shuts down if a single output draws too much current |
| OVP | Over-voltage protection | Shuts down if a voltage rises too high |
| UVP | Under-voltage protection | Shuts down if a voltage drops too low |
| OPP | Over-power protection | Shuts down if the whole PC draws more than the unit can deliver |
| SCP | Short-circuit protection | Cuts power at once if there’s a short |
| OTP | Over-temperature protection | Shuts down if the unit overheats |
Descriptions based on Seasonic’s explanations.
Fan failure protection
Some units also shut down if the fan stops. It’s less common than it should be. Lab reviewers noted it’s missing on the be quiet! Pure Power 13 M and be quiet! Dark Power 14, while the Corsair RMx (2024) and Corsair HXi (2025) include it. Without it, over-temperature protection is the backup.
Having them versus setting them
A protection only helps if it trips at the right point. Set too loosely, it may not act until damage has started. Lab reviewers test the trigger points and comment when they’re too high. For example, HWBusters found the over-current points on some minor outputs set loosely on the Corsair RMx Shift and too high on the Corsair SF Platinum (2024). Both are still excellent units, and those comments are about the smaller outputs, not the main 12V supply.
When protections trip in normal use
If a power supply shuts off during heavy gaming, a protection may be tripping. That’s it doing its job, but it usually means the unit is too small or not built for modern graphics card spikes. See PC shuts off under load.
What to look for when buying
- All six main protections listed on the spec sheet.
- Fan failure protection, if it matters to you.
- Lab reviews that test the trigger points.
Every unit on my list has the main protections. See what makes a good power supply.
- With fan failure protection · Tier ACorsair RMx (2024)80 Plus Gold · Fully modular · ATX · 750/850/1000WA quiet all-rounder that includes it.Check 850W price
- High power, with fan failure protection · Tier ACorsair HXi (2025)80 Plus Platinum · Fully modular · ATX · 1200/1500WFor high-end builds.Check 1200W price
Questions
Which protection matters most?
They work together. Short-circuit, over-power and over-temperature are the ones you’d least want to be without.
Do all power supplies have these protections?
Good ones do. Cheap unbranded units may list them without them working well.
What is OPP?
Over-power protection. It shuts the unit down if the whole PC draws more than it can safely deliver.
Can a protection trip by mistake?
Older units can trip on normal graphics card spikes. ATX 3.0 and 3.1 units are designed for them.
How do I reset a power supply after a protection trips?
Switch off at the back, unplug for a minute, then try again. If it keeps tripping, find the cause.
Sources
- Seasonic: protective features in power supplies
- HWBusters: Corsair RM850x Shift ATX 3.1 review
- HWBusters: Corsair SF850 ATX 3.1 review
- HWBusters: be quiet! Pure Power 13 M 850W review
- HWBusters: be quiet! Dark Power 14 850W review
- KitGuru: Corsair RM850x ATX 3.1 review
- Tom's Hardware: Corsair HX1200i ATX 3.1 review
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