The table below summarises the plug types, voltage and frequency of electrical current in both Benin and South Africa.
|Frequency of electrical current||50Hz||50Hz|
Benin uses Plug Type E.
You will need this adaptor:
Socket Type E
(Benin) to Plug Type M
The voltages found in Benin (220V) and South Africa (220V and 230V) are not exactly the same, but the difference is tolerable, so you should not need a transformer.
The frequency found in Benin and South Africa is exactly the same (50Hz). Timing devices and appliances that use motors will function as expected under this frequency.