You Do Need power plug adapter while traveling from Myanmar (Burma) to Sierra Leone.

Here is Why You Need An Adapter

The outlet and plug type used in Sierra Leone are D and G and in Myanmar (Burma) are A, C, D, G and I. This is how they look like.

Myanmar (Burma)

In Myanmar (Burma), outlets of type A, C, D, G and I are in use.

Type A

Type C

Type D

Type G

Type I

Sierra Leone

In Sierra Leone, outlets of type D and G are in use.

Type D

Type G