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

Here is Why You Need An Adapter

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

Equatorial Guinea

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

Type C

Type E

Northern Ireland

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

Type G