You Do Need power plug adapter while traveling from South Africa to El Salvador.

Here is Why You Need An Adapter

The outlet and plug type used in El Salvador are A and B and in South Africa are C, M and N. This is how they look like.

South Africa

In South Africa, outlets of type C, M and N are in use.

Type C

Type M

Type N

El Salvador

In El Salvador, outlets of type A and B are in use.

Type A

Type B