Type E vs. Type O

Type E is the French/Belgian standard -- unusually, its round grounding pin is fixed in the socket, not the plug. It's used across France, Belgium, Poland, Slovakia, and Czechia, and a hybrid CEE 7/7 plug design bridges it with the incompatible German Type F.

Type O is Thailand's standard, introduced in 2006 -- three round pins whose earth-pin offset happens to numerically match Type B's, letting Thailand's real-world hybrid sockets also accept American Type A/B and European Type C plugs. Pure single-standard Type O outlets barely exist in practice.