If the curling iron is dual voltage it's not going to blow any circuits. If you forget to switch it, you'll fry the curling iron, but usually that's all, because all appliances now are fused.

It's true that it will be on the "low" setting, but the higher voltage will mean that it's roughly the same as the "high" setting on North American voltage. On many dual voltage heat-producing appliances, putting it on 240 volts automatically puts it on low setting.

I bought a curling iron and small hairdryer on eBay years ago and love that I don't have to worry. I still have an adaptor since some countries use different prongs.

Don't know why this nearly 3 year old thread has been resurrected.