You Do Need power plug adapter while traveling from Tanzania to Isle of Man.

Here is Why You Need An Adapter

The outlet and plug type used in Isle of Man are C and G and in Tanzania are D and G. This is how they look like.

Tanzania

In Tanzania, outlets of type D and G are in use.

Type D

Type G

Isle of Man

In Isle of Man, outlets of type C and G are in use.

Type C

Type G