You Do Need power plug adapter while traveling from Burkina Faso to Saint Lucia.

Here is Why You Need An Adapter

The outlet and plug type used in Saint Lucia is G and in Burkina Faso are C and E. This is how they look like.

Burkina Faso

In Burkina Faso, outlets of type C and E are in use.

Type C

Type E

Saint Lucia

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

Type G