You Do Need power plug adapter while traveling from Northern Ireland to Equatorial Guinea.

Here is Why You Need An Adapter

The outlet and plug type used in Equatorial Guinea are C and E and in Northern Ireland is G. This is how they look like.

Northern Ireland

In Northern Ireland, outlets of type G are in use.

Type G

Equatorial Guinea

In Equatorial Guinea, outlets of type C and E are in use.

Type C

Type E