Type I vs Type O Plugs: Amperage & Pin Design Differences & Compatibility

Type I is a 3-pin, grounded plug rated 10A at 220-240V, while Type O is a 3-pin, grounded plug rated 16A at 220-240V. The two differ mainly in amperage and pin design, which is what decides compatibility — whether a Type I plug fits a Type O socket, and vice versa. For a related pairing, see type A vs type E plug.

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Type I power plug and wall socket
Type I
Type O power plug and wall socket
Type O
Standard AS/NZS 3112 TIS 166-2549
Pin Configuration Two angled flat pins (8mm long, 6.5mm wide, 30 degree angle) plus vertical grounding pin Three round pins in triangular pattern (4.8mm diameter power pins, 4mm grounding pin)
Grounding Grounded Grounded
Pin Count 3 3
Amperage 10A 16A
Voltage Range 220-240V 220-240V

Key Differences Between Type I and Type O

Here's how Type I and Type O compare, point by point.

  • Grounding: Both Type I and Type O are grounded.
  • Pin Size and Shape: Type I: Two angled flat pins (8mm long, 6.5mm wide, 30 degree angle) plus vertical grounding pin. Type O: Three round pins in triangular pattern (4.8mm diameter power pins, 4mm grounding pin).
  • Application: Type I is typically used for everyday household electronics and small appliances. Type O is typically used for heavy-duty appliances such as hair dryers, kettles, and heaters.

Type I and Type O Compatibility

Type I in Type O Sockets: Generally no. A Type I plug (Two angled flat pins (8mm long, 6.5mm wide, 30 degree angle) plus vertical grounding pin) does not fit a Type O socket (Three round pins in triangular pattern (4.8mm diameter power pins, 4mm grounding pin)) without a travel adapter.

Type O in Type I Sockets: Generally no. A Type O plug (Three round pins in triangular pattern (4.8mm diameter power pins, 4mm grounding pin)) does not fit a Type I socket (Two angled flat pins (8mm long, 6.5mm wide, 30 degree angle) plus vertical grounding pin) without a travel adapter.

If you're planning a trip, tell us which country you're visiting and we can confirm whether you need a Type I or Type O travel adapter. Compare this with type G vs type M plug.

Does a Type I plug fit into a Type O socket?

Generally no. A Type I plug (Two angled flat pins (8mm long, 6.5mm wide, 30 degree angle) plus vertical grounding pin) does not fit a Type O socket (Three round pins in triangular pattern (4.8mm diameter power pins, 4mm grounding pin)) without a travel adapter. You might also want type M vs type N plug.

Are Type I and Type O plugs the same?

No. Type I follows the AS/NZS 3112 standard and Type O follows TIS 166-2549 — they differ in pin design.

Which countries use Type I and Type O plugs?

Type I plugs are used in 24 countries, including American Samoa, Argentina, Australia, China, Christmas Island. Type O plugs are used in 1 countries, including Thailand.

How can you tell a Type I plug from a Type O plug?

A Type I plug has two angled flat pins (8mm long, 6.5mm wide, 30 degree angle) plus vertical grounding pin, and is grounded. A Type O plug has three round pins in triangular pattern (4.8mm diameter power pins, 4mm grounding pin), and is grounded. The quickest tell is pin size and spacing — compare the two pin configurations above.