You Do Need power plug adapter while traveling from Myanmar (Burma) to Saint Helena.

Here is Why You Need An Adapter

The outlet and plug type used in Saint Helena is 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

Saint Helena

In Saint Helena, outlets of type G are in use.

Type G