Type B vs Type M Plugs: Voltage & Pin Design Differences & Compatibility
Type B is a 3-pin, grounded plug rated 15A at 100-127V, while Type M is a 3-pin, grounded plug rated 15A at 220-240V. The two differ mainly in voltage and pin design, which is what decides compatibility — whether a Type B plug fits a Type M socket, and vice versa. Also see type F vs type K plug.
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Type B
|
Type M
|
|
|---|---|---|
| Standard | NEMA 5-15 | BS 546 (15A) |
| Pin Configuration | Two flat parallel pins plus round grounding pin (4.8mm diameter) | Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter) |
| Grounding | Grounded | Grounded |
| Pin Count | 3 | 3 |
| Amperage | 15A | 15A |
| Voltage Range | 100-127V | 220-240V |
Key Differences Between Type B and Type M
Here's how Type B and Type M compare, point by point.
- Grounding: Both Type B and Type M are grounded.
- Pin Size and Shape: Type B: Two flat parallel pins plus round grounding pin (4.8mm diameter). Type M: Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter).
- Application: Type B is typically used for heavy-duty appliances such as hair dryers, kettles, and heaters. Type M is typically used for heavy-duty appliances such as hair dryers, kettles, and heaters.
Type B and Type M Compatibility
Type B in Type M Sockets: Generally no. A Type B plug (Two flat parallel pins plus round grounding pin (4.8mm diameter)) does not fit a Type M socket (Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)) without a travel adapter.
Type M in Type B Sockets: Generally no. A Type M plug (Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)) does not fit a Type B socket (Two flat parallel pins plus round grounding pin (4.8mm diameter)) without a travel adapter. Compare this with type A vs type K plug.
If you're planning a trip, tell us which country you're visiting and we can confirm whether you need a Type B or Type M travel adapter. Next, check difference between type J and type N sockets.
Does a Type B plug fit into a Type M socket?
Generally no. A Type B plug (Two flat parallel pins plus round grounding pin (4.8mm diameter)) does not fit a Type M socket (Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)) without a travel adapter.
Are Type B and Type M plugs the same?
No. Type B follows the NEMA 5-15 standard and Type M follows BS 546 (15A) — they differ in voltage rating.
Which countries use Type B and Type M plugs?
Type B plugs are used in 54 countries, including American Samoa, Anguilla, Antigua and Barbuda, Aruba, Azores. Type M plugs are used in 9 countries, including Andaman & Nicobar Islands, Eswatini, India, Lakshadweep, Lesotho.
How can you tell a Type B plug from a Type M plug?
A Type B plug has two flat parallel pins plus round grounding pin (4.8mm diameter), and is grounded. A Type M plug has three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter), and is grounded. The quickest tell is pin size and spacing — compare the two pin configurations above.