imac trips circuit when starting the system

Amazing, there are so many posts about this problem and apple does nothing.

I have an iMac G5 20" 2.0Ghz which I purchased in Oct 05. 80% of the time I power on or wake it from sleep it trips my breakers. (brand new house with modern wiring) No matter what outlet I plug the iMac into in the house, it trips the breaker. I have a top of the line APC UPS with line conditioning, surge protection and all the bells and whistles. Yet still the UPS trips into battery mode and the breaker trips!

I originally thought this a problem of the APC unit and went through lengthy discussions with APC and a replacement unit sent to me. The original was found to have nothing wrong with it and everything still happens with the new unit. And obviously it is happening without the iMac connected to the UPS. I even went to the lengths of having our builders electrician check our breakers and he monitored the line draw to be too high when powering on the iMac - yet nothing else is connected to that breaker!

Regardless of the UPS the circuit trips. Obviously the iMac has something faulty with its draw on power upon waking or powering on or maybe a grounding issue.

Please, someone help all of us figure this one out as I am so sick of running down to the basement to reset the breaker almost every time I use my Mac! Lets get it together Apple - supprt your product and admit the mistake!

iMac G5 20" 2Ghz Mac OS X (10.4.7)

I must say I agree I received my computer yesterday and can hardely use it. Although I am getting good excersize running to the basement and back.... This is ridiculous! I called Apple tech support and it seemed almost like a new problem when I mentioned it. I don't want to have to install a nucleur reactor just to use a computer!

Have you found a solution to your problem yet. I am now having the same problem with my imac after moving to a new house. Worked fine in the old house trips circuits in the new house.

Hello,

You present a very interesting situation 😉

I am actually more suspicious that you have an unknown / recently occurring problem in the circuits in your room / house.

At first glance, the fault would appear to be that of the iMac. But, your UPS description would indicate that the problem is not with the computer.

You don't mention the brand of UPS that you use. But, most quality UPS brands have an over-voltage indicator.

For example, if I even try to run any of my Laser Printers from one of my APC UPS units, then I get an alarm telling me that something is wrong. If your iMac even momentarily drew too much power from your UPS, you should have a light and alarm that sound on the UPS.

Note that in my example, there is nothing wrong with my Laser Printers. They just draw more power than the UPS can provide through it's battery circuit. The UPS does not complain if I plug the Laser Printer into the Surge Protection Only socket.

But, if your iMac has a fault that causes it to draw too much power, then the UPS should fail to power it and provide you with an audible alarm and flashing light.

The second thing that tells me it most likely is not the computer, is that you claim to have tried it with both the UPS and several "power bars". Now, for the time being, I'll avoid the power bar lecture (you should be using surge protectors not power bars). But, here's the important / relevant detail:

Almost all Power Bars, Surge Protectors, and UPS units have a circuit breaker / over-voltage protection button built-in. That button / breaker / fuse (whatever it is on your unit) should trip well before the circuit in your house.

If the iMac is drawing more power than your house circuit can safely supply (assuming nothing is wrong with your house's circuit), then the breaker on your power bar / UPS should have triggered.

In that case, the breaker on the power bar would have tripped, and your house's circuit would have remained on.

The breaker on the power bar is rated to trip before the level that your house's electrical circuit is supposed to be rated for.

The fact that the breakers on your power bars, surge protectors, and UPS units don't blow tells me that your iMac is operating within the limits that your house circuit should handle.

The weak link appears to be your house circuit.

I would have your wiring investigated, and see if it's either got a problem or wired to be overly sensitive.

It is possible for those types of Arch-Fault protection circuits to trip before they should if there is a problem in the circuit or if they are wired differently. For example, when we were installing ours, there was mention in it's installation sheet that if I certain conditions were met in my wiring, that the circuit would be more sensitive than intended.

Anyway, consider the thoughts mentioned above in relation to the breakers on your power bars and UPS units. And, consider getting the wiring in your house circuit tested and evaluated professionally.

I hope this helps.

Let us know if you have other questions.


P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.

Hello,

I don't know why it would be tripping the power circuit in those rooms.

But, those Arch-Fault circuits are looking for a particular type of signal that would indicate a nail being punched through a electrical wire. For example, hanging a picture on the wall.

The possibility here is that the circuit is falsely sensing something that it mis-interprets as a wire being punctured.

It's also possible that you may have a wire that is weak, or perhaps the circuit is just weak for some reason.

I really don't know exactly why you would be having the problem you are. I am just throwing-out ideas.

I did take a look at my breakers, and they are 20-amp breakers. So, it is possible that perhaps the 15-amp ones are just more sensitive.

But, there should only be two items that trip that kind of breaker:

1) over-voltage (which seems to be rule-out).

2) something that provides the same type of line signal as a nail going through the wires.

I would still consider having the wiring professionally inspected with a description of the problem being provided to the electrician.

But, you could still call Apple and explain to them the problem you are seeing, and perhaps they will ship you another computer. It would be very rare for a computer to send the kind of signal that would trip your arch-fault interrupter. But, it's not impossible.

So, I guess those are pretty much the options I see.

I hope this helps.

"purchased in Oct 05"

So, it's under warranty for another month.

Haven't read many posts like this at all in the past two years. No problems with any of mine in either a fifty year old house with admittedly flawed wiring, or in a recently and cheaply built apartment.

Do you have a breaker that is GFI protected? They frequently fail. I have also encountered faulty breakers that are not GFI protected. I this house, I have had one GFI failure and one regular breaker fail. Both were 12 years old and from the same manufacturer. If the iMac is at fault, it should trip the UPS breaker unless it is a GFI problem.

You could put your iMac on a different branch circuit to see if it occurs there. An extension cord will do the trick so you don't have to move you iMac.

has the mac been pat tested? can you get it pat tested?