You Do Need power plug adapter while traveling from Senegal to Channel Islands (Guernsey & Jersey).

Here is Why You Need An Adapter

The outlet and plug type used in Channel Islands (Guernsey & Jersey) are C and G and in Senegal are C, D, E and K. This is how they look like.

Senegal

In Senegal, outlets of type C, D, E and K are in use.

Type C

Type D

Type E

Type K

Channel Islands (Guernsey & Jersey)

In Channel Islands (Guernsey & Jersey), outlets of type C and G are in use.

Type C

Type G