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

Here is Why You Need An Adapter

The outlet and plug type used in Chad are C, D, E and F and in Saint Lucia is G. This is how they look like.

Saint Lucia

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

Type G

Chad

In Chad, outlets of type C, D, E and F are in use.

Type C

Type D

Type E

Type F