Question for those of you who understand electrics…

I recently swapped PSU. Went from a 850W to a 1200W, both Corsair.
I have been troubled with the fuse to the wall socket tripping, when turning on power for the power strip, for everything needing electrical power for the SimBox. I thought it was the total load momentarily exceeding the 16A fuse, but I had an electrician to check that for me, and it was not the case.
Anyway, it seems like this problem was associated with the old 850W PSU.
My question is: What could cause this issue?

Sounds like the power strip is under rated if its fuse pops when plugged in.
And even though you had an electrician say ok, just makes sense that it’s
due to higher output power supply - instantaneous current.

ps and you did ground the new supply according to instructions, correct?


Do you have multiple things plugged into a power strip and once you plug the power strip in it trips the breaker? If so easiest thing to do is unplug everything and then plug the stirp into the wall and start plugging things in one by one until it trips. Last thing plugged in is the culprit.

Also as @piper alluded to this sounds like a ground issue,

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When you say tripping, what is tripping? The main RCD (Residual Current Detector) or the individual fuse for the socket ring main?

I know UK and Euro is different, but the principal of a ring main with a fuse for that ring should be universal.

Usually things “tripping” is that there is a leakage to ground somewhere, hence I’d go with @weaponz248 suggestion.

It might be there is a faulty earth in one of the devices.

Keets caution - I have UK electrical knowledge, you are not in the UK, so YMMV.


That is because all electronic/electric equipments that have components that storage energy like capacitors and coils when they turn on they usually “eat” +/- 2 to 3x more current in a short spike than when in nominal working, if the power of the psu is bigger usually their components by construction have bigger values to afford their higher power, so that spike to charge the capacitors is bigger, as so you have that spike that before you not had.
For example because this insta spike on the start, its why exist the star-triangle starting scheme in high power tri-phase electric engines to reduce that starting spike and so making the engine start with a single voltage per coil and after few seconds going to a composed voltage. Sqr(3)x ( +/- 1.73x higher).

So, that is normal, to avoid it you can put between the wall and the pc a good UPS. and try to reduce the load (equipments already on) when you turn your new PSU to reduce the surge spike.

Also what where triggered? the circuit breaker or the diferential circuit breaker? the circuit breaker protect against high current, the differential one protect against leaks or current/voltage on the ground cable (different situations/sources of problems that can turn trigger each one).


Thanks for replying guys. As you all seem to be aware of, we are all in different countries, so our electrical systems work a bit differently.
I’ll try to explain the details by answering your questions.

The power strip actually has got a 10A fuse, that doesn’t trip/pop. It’s the circuit breaker in the house fuse box that trips and shuts down that ring. When I reset it, I can start the PC.
The power strip is rated at 2300W, so it should be fine…

The powercord has its own ground, so the PSU is grounded via the house electric power grid.

I mean that the 16A circuit breaker in the house fuse box shuts down the power to that line/ring.

It’s the other way around.
The problem went away when I installed the new and bigger PSU. It seems like it’s the old and smaller PSU that was the problem.

I guess what I’m asking is if I should just bin the old PSU, or if there’s a way to fix it…

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It could very well be that the bigger, newer PSU has better compensation for the reactive power spike on power-on. As long as it works correctly otherwise, that alone shouldn’t be a reason to discard it.

Does the fuse breaker still trip when you turn on the PSU by its own switch and not together with the other appliances connected to the strip?


Fixing power supplies is achievable but you’ve got to diagnose the problem first.

With all the connectors now off your mobo and PC, I’d try plugging the power supply in on its own in a different ring main to see if that now trips.

Edit: or what @sobek said. Just seen he already responded the same.

If it does, congrats, you know the PSU has an issue.

What it could be though is a heap of things. Faulty diodes, faulty capacitors. If it’s leaking to ground, it could even be an issue in the rectifier in the transformer.

Trying to diagnose all that will depend on your knowledge of power supplies and electrics and electronics, but could be a ballache. You’ve then got to decide how well you trust your “fix”.

Before you bin it, how old is it? What make is it? Edit: Corsair, you said in your first post. :confounded:

I returned a Corsair 650W PSU under RMA after it’d been in my PC for 2 years.


Hm… I need to check if it still triggers the breaker, now that it’s out of the PC.

Need to check. I think the warranty has expired, but it’s worth a shot.

Do check, because different PSU’s have different warranty. I think my 650W had a 5 year RMA warranty.

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ohhhh ok, so it was the 850w the faulty one, my bad that i read it wrong.
Ok so if what trigger is the circuit breaker, is a surge or short circuit inside that make it trigger, if its the differential circuit breaker, so its a leak to the ground.

Also if it still works and its only a spike that sometimes triggers that circuit breaker on the turn on and the new psu not do that, the initial spike is the guilt, some equipments try to charge their capacitors too fast with high current and not have any delay circuits to avoid that initial high current load.