You Do Need power plug adapter while traveling from New Caledonia to South Africa.

Here is Why You Need An Adapter

The outlet and plug type used in South Africa are C, M and N and in New Caledonia are C and F. This is how they look like.

New Caledonia

In New Caledonia, outlets of type C and F are in use.

Type C

Type F

South Africa

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

Type C

Type M

Type N