My new 1275W PSU trips the circuit breaker

Jimmy Scribbles · May 9, 2014

My power supply unit -1275W trips the circuit breaker whenever any additional components are plugged into a socket in the same room, such as my LCD monitor. Is there some sort of adapter I can buy that limits the current the PSU can use? If not what is the best solution? I spent a lot of my money on building this PC but now I can't use it. I can run the PC when nothing else is plugged in, but as soon as i turn the power on for something else tje power for the whole floor trips. Any help is really appreciated!

Someone Somewhere · May 9, 2014

Remove some load from the PSU. Underclock (or reduce the OCs), or pull HDDs/fans.

Also turn off any heaters or lamps on the same circuit.

Jimmy Scribbles · May 9, 2014

Someone Somewhere :

I have it with only the necessities, and I cannot underclock as I need my components to run at normal efficiency. It only runs the cpu fan which I need to run. The reason it is a fairly large psu is to run several gpus, but the point is I cannot run it much lower when I get my gpus plugged in. Would an inverter work for the time being? What are the best solutions other than getting a technician to raise the current in the sockets as I may move house soon. Thanks for your time

techgeek · May 9, 2014

I assume that this is a 120V system (you live in North America) and that it's probably a 15A circuit breaker. That is the normal maximum for a 120V line. A 15A breaker trips at an instantaneous load of 15A, but it's only rated for 12A continuous which is what you have in your case. You can't limit the amount of current going to the power supply because it draws what it needs to power your system. If you could put a limit on it, instead of the breaker tripping, the computer would shut off which would give you the same result minus having to run to the breaker box to reset the breaker.

However you may have a faulty 15A breaker which is tripping before it hits 12A/15A. An electrician can replace the breaker. Actually you could probably do it, but there are issues with insurance and you working on your electrical system and not being an electrician.

If however, it is actually hitting the 15A on that circuit, your only other choice is to plug the computer into one circuit and move everything else to another circuit. Depending on how your house is wired, you could have more than a single set of outlets on that circuit. You could even have the lights in that room on the same circuit. To find out if you have another plug in that room that isn't on the same circuit, turn the breaker off that keeps tripping. Using something like a lamp (if you don't have a multimeter) plug it into different power outlets in the room until you find one that lights the lamp. This outlet is on a different circuit. Then plug all the other stuff into that outlet. Hopefully it's relatively close to your computer or you'll have to find a way to hide ugly extension cords.

Jimmy Scribbles · May 9, 2014

techgeek :

I assume that this is a 120V system (you live in North America) and that it's probably a 15A circuit breaker. That is the normal maximum for a 120V line. A 15A breaker trips at an instantaneous load of 15A, but it's only rated for 12A continuous which is what you have in your case. You can't limit the amount of current going to the power supply because it draws what it needs to power your system. If you could put a limit on it, instead of the breaker tripping, the computer would shut off which would give you the same result minus having to run to the breaker box to reset the breaker.

However you may have a faulty 15A breaker which is tripping before it hits 12A/15A. An electrician can replace the breaker. Actually you could probably do it, but there are issues with insurance and you working on your electrical system and not being an electrician.

If however, it is actually hitting the 15A on that circuit, your only other choice is to plug the computer into one circuit and move everything else to another circuit. Depending on how your house is wired, you could have more than a single set of outlets on that circuit. You could even have the lights in that room on the same circuit. To find out if you have another plug in that room that isn't on the same circuit, turn the breaker off that keeps tripping. Using something like a lamp (if you don't have a multimeter) plug it into different power outlets in the room until you find one that lights the lamp. This outlet is on a different circuit. Then plug all the other stuff into that outlet. Hopefully it's relatively close to your computer or you'll have to find a way to hide ugly extension cords.

The whole room is on the same circuit, could I just get a technician to allow more current through?

coolguybaddude · May 9, 2014

Well you can but in such case be warned that if some machine due to any short circuit or other fault "god forbid' might be dangerous as they will be able to overload themselves beyond the prescribed limit.
Any faults in such cases may also lead to warranty loses if the company guy gets to know of higher than permitted amount of current drawn.
But if your other electronics are reliable & you ought to move soon to a new house so you can make this sort of temporary arrangements.
Be sure same is not the case with the new house

Be sure to ask further & choose a solution worth helping others with similar problems...

Jimmy Scribbles · May 9, 2014

coolguybaddude :

That is very helpful thank you, has anyone else experienced this and found the best solution?

coolguybaddude · May 9, 2014

Well if someone had the solution then you neednt create a new thread for this & a simple google would have helped you out redirecting to the thread.
Simple solution to this is if you want more power then you draw more power. So if someone is to hinder in between power transfer it has to be eliminated or simply reduce your greed for power.

sunder25 · May 9, 2014

The only solution is to have an electrician change the circuit breaker to one with a higher amp rating. But as others have said, the house wiring must be rated to carry higher current, otherwis you risk wire damage leading to a short or worse, a fire.

Jimmy Scribbles · May 9, 2014

coolguybaddude :

Jimmy Scribbles · May 9, 2014

Thanks for your help guys I really appreciate it!

Someone Somewhere · May 9, 2014

I'm a little uncertain about the 12/15A thing. I'm in a 230V country, so things may be different. But I looked up the current curve for the breakers in my switchboard (Merlin Gerin C60N, C-curve, 10-32A depending on circuit), and the rating on them is continuous current, with instantaneous trip at 7-10x rated current.

techgeek · May 9, 2014

The rating on North American breakers is instantaneous, for continuous loads it's 80%, some say 85%. So a 15A breaker is good for a continuous power draw of 1440W (120V X 12A). Of course there will be some small variance due to different manufacturers and the manufacturing process itself.

As for just changing the breaker for one rated higher, that isn't advisable without the advice of an electrician. 15A services are spec'd to use 14/2, 20A are spec'd to use 12/2, and 30A services are spec'd to use 10/2. The wall sockets are different as well. The danger in using a higher current rating than the wiring in your house is that the wiring will get hot, possibly melting the insulation and causing a fire.

Someone Somewhere · May 9, 2014

That's a pretty big difference from here, then... if I used the instantaneous rating, my circuits are good for 140-200A...

Actually, it looks like that's a myth, from some googling.

But upsizing breakers is a very bad idea. Think more potential for house fires, and more serious electrocutions.

techgeek · May 9, 2014

Someone Somewhere :

Which part is a myth?

Someone Somewhere · May 9, 2014

It looks like it's a myth that the rating is instantaneous.

http://goodsonengineering.com/wp-content/uploads/2011/08/CircuitBreakerMyths_web.pdf

Jimmy Scribbles · May 10, 2014

Ok, so I bought a smaller power supply of 800W, and this trips the power as well. the first supply needed 15A, but this new one only needs 12.5A, is it because I had my laptop (which requires 4.4A) plugged in at the same time? I also had some other things such as an alarm clock plugged in and my lights. Would removing these allow my computer to run? I can't risk tripping the power again. Thanks in advance

Someone Somewhere · May 10, 2014

Changing the size of the PSU does not change the current significantly; it only draws what it needs to.

I'm picking you have a defective breaker. What are the lights?

hunter315 · May 11, 2014

A 15A breaker will NEVER trip for any load under 15A, as someone who has spent wayyyyy too much time at work looking at fuse and circuit breaker datasheets i can tell you that the "a 15A breaker is good for a continuous power draw of 1440W (120V X 12A)" is a load of crap, and I'll even give you proof to back up my statements! (shocker huh?)

A Square D QO breaker is a fairly common domestic circuit breaker, you can pick it up for $7 at home depot, its the nice one with the red window when it trips. Breakers are not magic, the current flowing through them has to generate force to trip them so they take some time, for most things you need to pull ~5x the rated current through it for a reasonable trip time. The Square D QO breaker has a trip time of 1 second when you are at 5x the rated load, so you have to pull 75A through that breaker to trip it in less than a second. Refer to page 19 onward of the datasheet
http://www.grainger.com/ec/pdf/QO-QOB-Miniature-Breakers-Catalog-2008.pdf

Now, we still haven't established what the OP is doing when the system trips the breaker, or if there is anything else on that breaker. OP do you live alone or with others? If you live with others i suggest flipping that breaker to off one day and seeing if someone complains that something isn't working that you don't expect, occasionally wiring is done weirdly and you have an outlet on your circuit you don't expect.

Someone Somewhere · May 11, 2014

That's basically what I linked above. Good to see I'm not going insane.

That's all good advice.

ko888 · May 11, 2014

Is the breaker an Arc Fault Circuit Interrupter (AFCI) type breaker? These are notorious for nuisance tripping especially when the PSU has a large inrush current.

Someone Somewhere · May 11, 2014

It looks like this is 120VAC, not 230VAC.

techgeek · May 11, 2014

I was going from this:

Max Power Link

He sources the NEC (National Electric Code), and I didn't say the breaker would trip at 12A. The load rating for a continuous load (greater than 3 hours) is 80% of the maximum. So I would assume a circuit using a 15A breaker is wired 14/2 which would be the limiting factor for a continuous load of 12A. The smaller the conductor the hotter the wiring will get under a specific load. So just changing out the breaker for a higher amperage breaker could be dangerous if you don't have the correct wiring to handle it.

Someone Somewhere · May 11, 2014

I'm 99% sure that's wrong.

Many devices (switch mode power supplies and electric motors being the main culprits) have inrush currents many many times that of the continuous current. I'd have to get out a lot of measuring equipment, but e.g. a fridge probably draws upwards of 20A, even at 230V. I've run 2.4kW rated heaters (rated at 240V, we use 230V±10% IIRC) on 10A rated power strips.

ko888 · May 11, 2014

Someone Somewhere :

Were they on an AFCI breaker?

My new 1275W PSU trips the circuit breaker

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