I think I have found a solution to the problem that many people have with newer Mac Pros plugged into bedroom circuits that are on AFCI circuit breakers. For me, the breaker would trip almost every time that I started my Mac Pro, even though it was on a good UPS. I scheduled the computer to startup automatically every morning in the energy saver preferences. So far, the computer has started up without tripping the circuit breaker.
If your Mac Pro trips an AFCI breaker every time you turn it on, you really should have an electrician check the circuit. That's not proper behavior, and I know it's not universal. Look for a bad neutral connection somewhere along the circuit.
The UPS won't make any difference at all unless it's always on-line, and you probably didn't spend more on the UPS than you did on the Mac Pro.
Did you ever figure out what the source of the problem was? My breaker trips every time i power on the mac. Its on an AFCI circuit, so I tried running an extension cord into the bathroom and it tripped that circuit as well. This is so frustrating.
It has to do with the Power Supply in the Mac. It would appear that the Mac Pro doesnt have Active PFC (power factor correction). PFC is intended to reduce the higher harmonic noise on the power lines generated by the high frequency switches in the power supply. Every switching power supply will have slightly different noise characteristics. You want to find one that doesn't cause false tripping of your AFCI breaker. Unfortunately it might be a case of trial and error finding a supply that will work for you.
This is a more common issue with people that are building their own PCs as opposed to Mac Pros having the issue, you might be able to get Apple Care to swap out your power supply and maybe it will solve your issues.
You're making a lot of assumptions and just plain guesses about the engineering of Apple's UL and CSA approved and certified power supplies. The problem is much more likely to be with the house wiring in this case. I can't get a Mac Pro to trip a properly installed gcfi breaker at my house and I doubt it's an overall design problem.
Thanks - this is the most concrete information I've received so far. One weird thing is that the circuit has tripped just from plugging it in. I didn't even turn it on yet.
My electrician had me go to Apple after he saw the 2 PCs, Mac G4, XBox, Playstation 3 and vacuum cleaner all working at the same time on the same circuit.
Apple Care is swapping out the power supply, but it feels like a stretch to me. Nobody seems to be able to pinpoint the problem.
Its not a GFCI breaker that is the issue that we are talking about we are talking about AFCI.
AFCI vs GFCI
The AFCI should not be confused with the GFCI or ground fault circuit interrupter. The GFCI is designed to protect people from severe or fatal electric shocks while the AFCI protects against fires caused by arcing faults. The GFCI also can protect against some electrical fires by detecting arcing and other faults to ground but cannot detect hazardous across-the-line arcing faults that can cause fires.
A ground fault is an unintentional electric path diverting current to ground. Ground faults occur when current leaks from a circuit. How the current leaks is very important. If a person’s body provides a path to ground for this leakage, the person could be injured, burned, severely shocked, or electrocuted.
The National Electrical Code requires GFCI protection for receptacles located outdoors; in bathrooms, garages, kitchens, crawl spaces and unfinished basements; and at certain locations such as near swimming pools. A combination AFCI and GFCI can be used to satisfy the NEC requirement for GFCI protection only if specifically marked as a combination device.
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So if you had bothered to research issues with computers tripping AFCI breakers you would see that it is a common issue. The sudden surge of power that most computers make can be enough to cause the AFCI breaker to trip. There are sensors inside the breaker that monitors the power flow will de-energize the circuit within miliseconds of detecting the power surge.
It tripped both the GFCI and AFCI circuits - one in the bathroom (GFCI) and one in the bedroom (AFCI). What was I supposed to research? I was afraid to plug it into a non-protected outlet at that point.
How about showing us your research indicating that it's a common problem on a properly wired circuit? I've seen several cases of it, all cured by fixing the wiring.
direwolf8 wrote:
How about showing us your research indicating that it's a common problem on a properly wired circuit? I've seen several cases of it, all cured by fixing the wiring.
Drake Dasterly
Tech Level: average
Ownership: 1 week to 1 month
This user purchased this item from Newegg
5/15/2007 10:36:37 PM
Trips Arc Fault Breaker
Pros: Purchased the power supply to be able to install a new graphics card in a HP PC. The ST56F feels solid and has good looking black paint on the exterior. The 2 six pin PCIe connectors are sleeved as well as the motherboard power connectors. The drive power cables are not sleeved. The power supply fan is not audable over the other fans in the chassis. It is really more power supply for what I need. I am hoping the extra wattage means it will be able to keep up with any future upgrades.
Cons: *I have a newer home with Arc fault breakers in the bedrooms. This power supply trips them. Silverstones tech support suggested I plug the supply dirrectly into the wall outlet. This had no effect. The AFCI in the breaker panel works fine with other computers and is working correctly. As far as I can tell it is an inrush current issue. I would send it back, but I am fairly sure I would get the same results from the replacement.*
Other Thoughts: I almost returned the supply. Instead I moved the computer to another room. Not really the best solution. I am still considering other solutions, including purchasing another power supply (from New Egg naturally) and using this as spare.
