Will it cause any damage to iPhone charging at 50 hz which is rated between 56-60hz

NO. In my opinion, such a small difference (6 per second) should be nothing to the transformer inside. Plus, when I was in china, the 50Hz 20V AC power didn't did any damage to the plug, and I am still using that plug to charge my Powerbanks, and there is(if there is, I cannot either hear it nor observe it.) Also, think that it is labeled 50Hz~60Hz, if what I remembered is not wrong.
All in all, it is totally OK.

• Answered by Xavier J from Kansas City
• 11 17, 16
• Flag as inappropriate Answer 1