Sometimes my phone will not charge when I put it on the wall adapter. I have 3 adapters, my original, my GF's original, and a Griffin one. Randomly my original (I keep at work) and the Griffin will not charge the phone. When plugged into my original, if it's not going to work, it will not change the iPhone's display at all, as if it's not plugged in to anything. If the Griffin isn't going to work, it will change the battery icon to show a plug, but never a lightning bolt (actually charging). My GF's will always work, and once I plug it in to hers and get a lightning bolt icon, I can switch it over to my Griffin and it will work. Plugging it into my comp always works too (with the same usb cable as is connected to my original charger at work) Any ideas? I took it to the Apple store the first time this happened and they couldn't duplicate it. I've never damaged my phone.