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HX850 Tripping AFCI Breakers


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When my PC is re-powering ( followed by a blackout / move / reassembly )

it's usually tripping my (230/10) AFCI Breaker..


When I'm trying it again...

(PSU off, AFCI on, wait 1-2 minutes just to bee sure, PSU on)

then one of the following things can occur:


1: the circuit breaker tripping again

2: it's powered on, and everything works fine after that.

3: bang.. smoke.. the PSU is burned down (this is my 2nd hx850)


Is it really pick up more than 2,3 KW on startup?

- do I need to replace the circuit breaker?

- should I rewire my house to power my PC? (lol)

- will this one die too, or I don't need to worry about it?

- any other suggestions?


Sorry for my bad English.

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I wouldn't rewire your house, but since this is the second PSU that did the same thing i would think about having an electrician at least look at it.


I know you said you used to power 4 PC's with the same outlet, but outlets and electrical systems fail too! :)

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Thanks for the quick reply..


I'm afraid about that no one can test/find anything that can cause a problem like this.

Of course, they can- and would rewire my room, but that would lightly help me out.


These problems start right after I replaced the PSU, so the question is only:

is this power supply really eats up more than my old 4 computers together !?

is it normal, that the input current can exceeds 10A ?


If it is, than I have no other choice then replace my circuit breaker.

(and hope that the wires itself can handle it)

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I think there is something wrong with your PC's wiring if you are tripping a 10A/230V AFCI breaker. A HX850 would never draw that much power, unless it is broken. Do not change the breaker to a larger one!


Your circuit breaker, of 10A at 230V, is 10A X 230V = 2300 Watts capacity.


A HX850, if it was providing 850 Watts to a PC, and is about 85% efficient (which it is) would use 850 / 0.85 = 1000 Watts of power from your circuit.


1000 Watts / 230V = 4.35A at the very most possible. A HX850 should never use even half of the 10A rating of your breaker. The 10A rating is for 100V (Japan), the manual does not show the correct Amperage use for a 230V supply.


In the science or rules of electricity, if the voltage is doubled (for example, from 100v to 200V) the current (Amps) is reduced by one half, for the same amount of power, in Watts. 1000Watts = 100V X 10A, or 1000Watts = 200V X 5Amps.


I have an i7-930 CPU in a PC, which uses the same amount of power as your CPU does. My surge protector outlet strip has a simple power meter on it. I also have a HX850. When I start that PC, with a monitor, the power meter shows I am using less than 200Watts of power. I'm in the USA, with 120V power. 120V X 2A = 240Watts, so I am using less than 2A when the PC starts. If I had 230V power, I would be using less than 1A, and so would you. The PC and monitor, when on the Internet, uses about 150Watts.


I hope I have showed you that your HX850 should never be using 10A of 230V power (2300Watts!!) Something is very wrong in the connection to that PC, like a short circuit from a bad cable or wire, maybe even the plug into the wall, or the circuit breaker is bad.


Do not use a larger power circuit breaker, in the US we usually use 1800Watt breakers, and sometimes 2400Watt on special circuits. I have never, ever, tripped a 1800Watt breaker in my PC room, even when I have two of them on, and lights, etc.


Is the PC plugged directly into the wall outlet, or something else? I don't really understand why your breaker opens or why your HX850 burned, something is wrong but it's not the HX850 using 10A of 230V power.

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Thanks for the reply!

That is exactly what I thought...


On the other hand, every newer electronics and power supplies comes with larger capacitors built in it, to filter the noise of the input power, and maintain the output level solid.


These capacitors can, and will pick up a big peak of current on the start.

(there's no way to measure the size of this peak with a power meter)


The power supply is automatically "switching" between 110-250V, so at the moment of the start, maybe it pick up a same amount of a current.

(I'm just guessing on this, I think only PSU engineers knows this for sure)


I read similar stories on the NET (even with a 15A breakers) the common suggestions are to replace the circuit breaker and the surge protector... (I have an "APC" surge protector)


There's also a chance that the PSU itself doesn't tripping the breaker, but with the monitors.

My previous Hx850 did tripped the breaker by itself (at the end), but maybe it was faulty.


I'm just afraid experimenting with this.

I really don't want to replace the PSU again..

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Your idea about the large filter capacitors in a AC to DC PS causing a very short but large power surge draw from the AC line is a well known phenomenon in general. That was noticed at first with the simple, "linear" PS design, that just use a transformer, rectifier bridge, and large filter/storage capacitors. Those PS's also do not contain an active voltage regulation stage, which I think suppresses the initial input surge somewhat.


Modern PC PS's are very different than that, being of the "switching" type PS. That type of PS has a lower initial input power surge, AFAIK. There are also components that can be added to a PS to limit or suppress the initial power surge, and are commonly used in high power PS's, really a standard thing today.


Regardless, the power surge issue should not be a factor in any modern PS. High power audio amplifiers with large linear PS's don't cause breakers to open when they turn on, or refrigerators, air conditioners, etc. I have never had this problem with any PC PS I have ever used (I've used many), and if it was common we'd be hearing about it all the time. The automatic AC voltage detection in PC PS's is common today, and should not be causing your problem. When a PS of that type is first turned on with the PC off, the voltage detection occurs and is done with, nothing more happens with that when the PC is turned on.


You might have a problem with that AC line, the wall outlet (not the breaker) or the breaker. What happens if you plug something else into that outlet, like a TV, stereo, etc? If you want to test a surge problem with the breaker, get a hand held hair dryer, turn it on high, and then turn it on. A powerful hair dryer will draw more power than most PC PS's.


Do you have another PS to try on that PC? An old one, or lower power model? I still think something inside the PC is causing a problem with the HX850, you need to check that thoroughly.

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This problem IS happening when the PS is plugged in, and I'm turning on the PSU switch.

(or when my room is regaining power)


After that, (if the breaker is still on) everything works fine, I can turn on the PC anytime, and use it without limitations.


So if these "modern" power supplies are not supposed to pull any big peak of current during its connection, then I have to believe that hx850 is just a badly designed/faulty model.


As far as I know the PSU doesn't suppose to overload the power lines, or trip the breakers, even if I have some hardware problems. I mean, thats what the "overcurrent protection" is for. right?


But I'm still hoping that I just have to bee careful, and connect the PC simultaneously every time after I lost power.

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Ok, now I understand what your issue is. I unplug and turn off and on my PSs all the time, and never had that problem. That does sound like it might be a problem with the automatic voltage system, but very unlikely you'd get two units with the same problem.


AFCI's can open for no reason at times, it's not uncommon for people to have problems with them. Do a Google search on AFCI and you'll see what I mean.


Can you try plugging in and turning on the PS in that PC in a room that is on a different breaker than your usual room? Just be sure the room is on a different breaker, and try it there. If you have no problem on another breaker, the first one is probably bad.


A PC power supply's over-current protection is not about limiting power through the AC line. It protects the PC components from to much DC power being delivered from the PS itself, such as in a short circuit in a component powered by the PS, or bad load that tries to draw more current from the PS than is safe.

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Ok, that's a good idea to test it out...


Just how I sad, I'm really afraid to experimenting with this.

This is my 2nd PSU, and I didn't want to replace it again.


It's not a common issue, but I did found some similar cases google-ing it..


I just thought, it is an obvious problem with this PSU,

or maybe every PSU larger than 800w, needs a 15-20A breaker.

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parsec I don't know why you always try to advocate Corsair products and blame everything else, wiring and circuit breaker in this case.


I also have a new HX 850W and it does the exact same thing.

The 10A/230V circuit breaker pops sometimes when I flick the switch on the back of the PSU.

The PSU has enormous current draw when powering up after being discharged. This is not normal for such a unit and is most likely a design flaw.

How come I can run a dishwasher topping at 2,1kW and several other appliances at the same time on one 10A breaker but the HX 850W alone on the breaker trips it?


Corsair has approved the RMA of this PSU but I don't feel like paying over 38€ to ship it so I'm looking for other solutions.

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I don't see a way to fix the PSU, at least not without opening it for inspection, which will void the 7 year warranty so I won't do it.


I will probably return the unit to the retailer for exchange, since Corsair approved the RMA for this unit they can't probably deny replacing it ASAP.

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I just thought, it is an obvious problem with this PSU,

or maybe every PSU larger than 800w, needs a 15-20A breaker.


That is correct and should be a minimum of 15 Amps for any PSU above 700 Watts. If you have more than one out let sharing the same breaker it is more then possible that you could be over loading the breaker.

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That is correct and should be a minimum of 15 Amps for any PSU above 700 Watts. If you have more than one out let sharing the same breaker it is more then possible that you could be over loading the breaker.

Nice.. my global breaker is only 16A.

Do I need to build an own power plant to energize my PC?

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