You Do Need power plug adapter while traveling from South Sudan to Pitcairn Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Pitcairn Islands is I and in South Sudan are C and D. This is how they look like.

South Sudan

In South Sudan, outlets of type C and D are in use.

Type C

Type D

Pitcairn Islands

In Pitcairn Islands, outlets of type I are in use.

Type I