Originally Posted by
Yaatri
Once again, it's the current and hence the thickness of the wires that are of concern between wiring for 220 and 100 V appliances.
The thickness of wires is, indeed, the main concern.
However, most wires used in North American appliances are rated at either 125V, 300V, or 600V. Virtually all consumer-grade switches are rated at ~125V. While, in practice, this is not very likely to cause a problem, the use of 125V-rated wires and/or switches would still,
technically, be a safety violation.