Faulty iPhone 5 Lightning USB cable drawing too much power when not attached to anything?

I have not had a lot of luck with cabled accessories that shipped with my iPhone 5. The Earpod that came with my iPhone 5 was replaced last week because the volume control and pause/play button did not work. The Lightning USB cable apparently went bad in the last day or so because it now causes my iMac to issue multiple error messages about a USB device drawing too much power. The interesting thing is that this happens even if nothing is attached to the other end of the Lightning cable. Just plugging the cable itself into the iMac causes this error message to appear. I verified that it is the cable that shipped with the iPhone by trying a spare Lightning cable I bought from the Apple Store. This second cable does not cause any issues. It looks like the "smarts" that Apple added to the Lightning cable is more trouble than anything else.