"Wall wart" on power supply too hot to touch

Question

"Wall wart" on power supply too hot to touch

I'm wondering if this is a normal condition or something to be worried about.

MacBook, Mac OS X (10.4.10), 2 GHz Intel C2Duo, 1 GB RAM

Posted on Jun 24, 2007 10:07 PM

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Answer 1

Jun 25, 2007 1:07 AM in response to Matthew_Treder

Yes, they're very warm, but not "too hot to touch".

It's only really too hot to touch if is actually burns you on contact (about 180F+). The flashpoint of most common household construction materials is far higher than this, so it isn't really a fire risk either.

There's also a number of safety measures and devices with junction breakdown temperatures in the power supply that will kill it if it gets too hot.

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Answer 2

Jun 26, 2007 8:44 PM in response to Alex Dawson

I guess that's what I was getting at. I had no idea it was getting so hot until I carelessly rolled onto the box while it was tucked somewhere in the bed linens. Crikey!

**** careless of me, but I can only plead ignorance. Afterward, I began to worry if thousands of us were unwittingly putting whole families at risk.

Sounds like a few clever engineers (as usual) were already two steps ahead.

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Answer 3

Jun 27, 2007 2:38 AM in response to Matthew_Treder

You should allow good air circulation to prolong its lifespan, and I don't think keeping it under your blankets is a great idea 🙂

I have worked with electrical engineers, who have introduced me to the concept of a .6 (60%) safety factor. This means that in any design, you include tolerances more than 60% above what is required for safety. I have no double Apple has done this too. This means things like if your device will spontaneously combust at 500 degrees, make it break at 250 degrees, and the like.

The only time you need to be really worried is with goods that are counterfeit (like some Apple batteries and power supplies from eBay). The rest of the time, you're likely to find very good safety factors in them 🙂

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