Can the usb sync/power cable that came with the iPhone 3g and 4 handle the 2.1 amps drawn by the ipad 2 (if used with the 10w plug) without risk of overheating?

Question

I recently made the mistake of buying a cheap sync cable from a well known auction site becuase I wanted a longer cable than comes in the box for my ipad 2.
Whilst my iPad will sync OK, it takes an age to charge (using the standard 10w plug in the wall). I don't fully understand the science in the cables, but assume it is not a big enough cable to handle the current/2.1 amps?.
If like house wire you send too much current through a cable that is to small for the job it risks overheating and causing a fire.
Does this same principle apply to the iPad power lead?
Anyway back to the question, can I use other leads I have hanging around the house from my previous iphones and ipods to charge my ipad (again still using the 10w plug in the wall) or will the cable in these be too small to handle the 2.1 amps required by the ipad?
I don't want to risk overheating the cables and causing a short to break my beloved iPad 2...!

Answer 1

Thanks for your replies.
Not sure they entirely answer my question though.
I have used my different cables and can see that they are actually working (charging and syncing etc), but am i using old cable that was not intended to draw 2.1 amps and so may overheat and cause damage in the long run?
Or did apple deliberately over engineer the original cables which were only needed to supply 1 amp and they can actually be used to draw 2.1 amps comfortably?
Whilst the 30 pin connectors and usb points are identical, is the internal cable thickness/awg gauge the same?
Thanks