Written by: Adam Christianson
In these days of countless stories of exploding Dell notebooks and massive Dell power adapter recalls, Apple has seemed relatively immune to these sorts of problems. Every once in a while, some odd thing came along, but it seemed like relatively calm waters. I fear, however, the sense of safety for Mac notebook users may be coming to an end. There have aready been hints of problems with the white brick adapters and scattered reports of various failures. Who can forget about the class action settlement around the previous Apple adapters?
Recently, I have had problems with my Apple PowerBook power adapter which has lead to me take a close look at their design and safety. With no apparent trigger, no visible damage or other warning of any kind, my adapter began to spew sparks and flames and burn the paper notepad on which it was sitting. Thankfully, I was literally sitting right in front of the adapter when it happened and I was able to instantly unplug it – but not before it damaged the paper notepad and my PowerBook. And it could have been much worse.
I was surprised that an adapter could possibly do something like this – it had to be a fluke, I thought. So I posted a page that showed photos and gave some details of my problem. This quickly attracted many thousands of visitors, some of whom contacted me to share similar stories with me. Fortunately none of them were injured, but reports ranged from simply needing a new adapter to their notebook being rendered a nearly useless five and half pound hunk of aluminum and plastic.
The fact this wasn’t entirely isolated piqued my curiosity. Talking to a few people associated with some Apple Authorized Resellers & Service Providers found they had seen this failure many times before. So what was causing it? Why did these adapters so easily short out and smolder or even catch fire? Could it be prevented? Has Apple made improvements in this department? Will it happen to me again or other users?
How It Starts
The adapter provides 24.5 volts of direct current electricity – enough to generate a bit of a spark when it arcs. In the case of the adapters that burn and spark near the DC out, the internal cable insulation wears down to the point that there is little insulation between the wires left. At some point, there’s just so little left, the cable is able to spark – potentially with no visible external triggers or warnings – and this spark is enough to cause the plastic to smolder and/or burn.
Obviously, the plastic used in the insulation is at least slightly combustible, as evidenced by my experience. Furthermore, it appears that it may be designed in such a way that the internal cable insulation is less durable than the visible external insulation. The result is that the cable appears to be perfect – at least on the outside – yet on the inside, it could be precariously worn. There’s no way a consumer could reasonably be expected know this or anticipate such a failure.
It seems Apple has been aware of problems in this area of the adapter. Early versions of the white brick adapters (such as the one on the snow iBook G3 I purchased years ago) used an inverted cone type design to reduce stress on the cable. However, it seems that wasn’t satisfactory, so Apple re-designed that area to be flat and placed a short rubber sheath that extends along the cable as it leaves the adapter. Unfortunately, it seems evident even that isn’t sufficient to mitigate the stresses that occur even in normal, careful use. Like many Mac users, I don’t roll my adapter cable around the small feet and have been very careful with my adapter, yet it still managed to short, spark and burn.
Don’t forget that Apple’s previous adapter designed have resulted in various recalls and even a class action settlement.
A Preventable Problem
Of course, combustible materials, poorly designed wire stress management and fragile insulation isn’t alone enough to start a fire. What makes this so dangerous is the fact that the Apple power adapters do not integrate sufficient short circuit protection on the DC side. This means, when the wires touch or nearly touch, they will arc and generate a spark – not once, but again and again, as long as the adapter remains plugged into electricity. And because it happens on the DC side, it does not trigger any circuit breakers, household fuses or GFCI outlets.
This is a huge problem – even my $35 PC ATX power supply will barely emit a single tiny spark before the entire thing powers itself off and requires me to disconnect and reconnect the power before it delivers any more current to the DC side. The Apple notebook adapters are a lot more expensive and – hopefully – better designed than the local computer store’s $35 special on a generic Chinese ATX power supply. Yet… why doesn’t the Apple power adapter turn off when it detects a short?
Still No Improvements
Now… everybody obviously asks, "Well, surely Apple has improved their adapters?" People have even written to inform me that Apple now uses "sturdier" cables on their newer adapters, so this problem shouldn’t happen anymore. However, unless they’re talking about a different adapter – maybe one of the new MagSafe adapters, which obviously don’t work with the PowerBook – they’re wrong.
I spent time closely inspecting the original adapter that came with my PowerBook and caused the problem, comparing it to the model Apple sent me as a replacement and another Apple branded power adapter I purchased new from a local computer store. They were all identical. The reinforcing rubber "bootie" was the same. The cable appeared to be the exact same gauge. They even all exhibited the same lack of proper short protection and proved able to arc endlessly without tripping any breakers, fuses or GFCI outlets.
Apple, I love the innovative and alluring design of your computers. I love how Mac OS X integrates the power of Unix with the strength of commercial software like Photoshop all wrapped into a stable, intuitive operating system. But, why can’t you design a safe, reliable power adapter, or at least fix your mistakes?