Many years ago, you could count on the tripping of the 110V A/C circuit on formal nights! That was attributed to all the women coming out of the shower and plugging in the hair dryers. On the old "Emerald Seas" it was a common happening. I think the newer ships have greatly improved the electrical systems, and supplied 220V hair dryers in the cabins to eleminate this inconvenience. I too would advise against irons in the cabins, if for no other reason to avoid onboard fires. Take a steamer, or do what I do, and don't worry about it!