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michelangelo33 · Nov 19, 2006, 11:00 PM

I just bought a Mac Pro and 20" display to replace my old Quicksilver system. After hooking it up and transferring the contents of my old Mac, it seemed to run very smoothly. Then, the computer went to sleep. I hit the space bar to wake it up, and the all the power in the room went out. I reset the breaker, and it happened again several times. I took it back to the Apple store and they said it was DOA and replaced it. After hooking it up again tonight, it happened again.

Why does waking my Mac cause a power surge in 1 room of my house??

mduell · Nov 19, 2006, 11:26 PM

Are you chaining 4 million devices on multiple power strips?

Is your house wired for some reasonable current (15A)?

michelangelo33 · Nov 20, 2006, 07:48 PM

No, the computer and monitor are plugged directly into the wall. I have no other peripherals attached.

I hooked it up to my old Studio display, and when I hit the power button on the Mac Pro the power went out again. This house is only 2 years old, so I imagine it could handle the Mac Pro.

chris v · Nov 20, 2006, 08:05 PM

Basic troubleshooting: move it somewhere in the house that you know is on another breaker. That seems really weird, and have never heard of it happening before. (though here at the shop, if someone puts bread in the toaster & soup in the microwave at the same time, it takes down the breaker with one of the art room Macs on it. PITA!)

Scotttheking · Nov 20, 2006, 08:06 PM

Just because the house is 2 years old does not mean the wiring was properly done. Check other circuits to see if it works there, as a first step.

Spliffdaddy · Nov 20, 2006, 09:55 PM

If the house is 2 years old it likely has 'arc-fault' circuit breakers on the bedroom circuits. These breakers are highly sensitive and can be troublesome when certain types of electronic gadgets are plugged in. Especially troublesome are power strips that have anti-surge protection or UPS.

Just a thought...

It should be obvious by looking at the circuit breaker if it's an 'arc-fault' breaker. There will only be 3 types of breakers. Standard, GFCI (for kitchens, baths, and outdoor), and arc-fault (bedrooms only).

Captain Curt · Nov 20, 2006, 11:00 PM

Did you use a different power cord with the newer Mac? Are you using a three prong power cord on a three prong power outlet? If yes to both questions, I would think the culprit might be in the ground of your house wiring. Have you ever felt a tiny tingle when you touched your Mac pro?

Is the serial number on the new mac pro diffrent from the old. They didn't mistakenly give you your old Mac back to you did they?

Was the old quicksilver still hooked up to your mac pro when you first had trouble?

Captain Curt · Nov 20, 2006, 11:58 PM

Sorry I was vaugue. Did you use a different power cord with the Mac Pro replacement?

michelangelo33 · Nov 21, 2006, 01:18 AM

It's definitely a different Mac. I used the 3-prong cord that came with the new Mac Pro and it is plugged directly into the wall.

I'm beginning to think that it is an electrical problem and not a problem with my Mac. It is located in a bedroom, so it very well could be an arc-fault breaker. If that is the case, do I need to move it out of the office? This room is a dedicated office, so I hope that is not the case.

We are consulting with an electrician tomorrow. Hopefully we'll find the cause.

michelangelo33 · Nov 21, 2006, 07:17 PM

UPDATE: Problem solved. It was indeed the arc-fault breaker. We had a different breaker installed and all is running well now. Thanks!!

rehoot · Nov 22, 2006, 01:10 AM

Even if your current power situation has been solved, you should consider getting an uninterruptible power supply. If the power goes out your computer has enough time to shut down gracefully or keep running until the power returns.

I run my Mac Pro, 23" monitor, and the power for my DSL from a 900VA supply. I have another supply for things like external hard drives and other goodies.

ebf1978 · May 29, 2007, 12:17 AM

I too have been experiencing the same problem. I'll try replacing the circuit breaker and post whether that solves the problem. It's still a bit surprising... thanks for your posts!

justmetoo · May 29, 2007, 12:54 PM

Originally Posted by rehoot

I run my Mac Pro, 23" monitor, and the power for my DSL from a 900VA supply. I have another supply for things like external hard drives and other goodies.

Sorry, not trying to hijack the thread.
I totally agree, a unit like the Mac Pro DEFINITELY needs a UPS, NEVER plug it directly into the wall. While you may be able to squeak by with a 900VA UPS on your set up, if you never turn your MP off, I'm thinking it will not have enough juice if you try to wake it to shut down properly in an extended power outage. Check out this ATPM article: ATPM 13.02 - How To: Demystifying the Uninterruptible Power Supply (UPS)

cgc · 06:55 PM

I went to the APS UPS selector and came up with 1300VA as a recommendation for my MacPro..

mduell · May 29, 2007, 03:20 PM

Originally Posted by cgc

I went to the APS UPS selector and came up with 13KVA as a recommendation for my MacPro..

WTF? A dual Xeon 5100 with 4 internal hard drives and a pair of LCDs will run fine on a 1500VA unit (only 30% of capacity used).

cgc · May 29, 2007, 06:56 PM

Originally Posted by mduell

WTF? A dual Xeon 5100 with 4 internal hard drives and a pair of LCDs will run fine on a 1500VA unit (only 30% of capacity used).

Hmmm, never noticed the capacity used part. I misspoke previously: not 13KVA but 1300VA.

brokenjago · May 29, 2007, 07:49 PM

My UPS is 1550VA and runs at about 25% capacity. I've never seen it go higher.

cgc · May 29, 2007, 11:12 PM

Originally Posted by brokenjago

My UPS is 1550VA and runs at about 25% capacity. I've never seen it go higher.

That may be under normal loading and is rated so much higher because your Mac can go that high under worst-case scenario.

justmetoo · Jun 1, 2007, 11:37 AM

I have a 1200 VA on my Mac Pro with nothing else but the monitor plugged in.
[NEVER EVER have a printer plugged into the power backup outlets of your UPS, the filtered side is OK though...printers are energy hogs]
I was able to wake the MP twice from sleep (don't ask why...) on UPS power alone. From what I understand, different UPS manufacturers use the same batteries, but for some reason the units show various performances...

There is a long-running thread at Apple discussions: APC users have major shutdown issues with Mac Pros waking from sleep on battery power...
Apple - Support - Discussions - 1500VA UPS + Sleepy Mac Pro Wakes Up = ...