You Do Need power plug adapter while traveling from Norfolk Island to Antigua and Barbuda.

Here is Why You Need An Adapter

The outlet and plug type used in Antigua and Barbuda are A and B and in Norfolk Island is I. This is how they look like.

Norfolk Island

In Norfolk Island, outlets of type I are in use.

Type I

Antigua and Barbuda

In Antigua and Barbuda, outlets of type A and B are in use.

Type A

Type B