The SSEG regulations apply to the entire SA.
The fact that one’s Munic does not enforce that today is a problem that is coming one’s way tomorrow
To play it safe, to be Future Proof, rather safe than sorry, install as if it will be enforced tomorrow, or you will be forced to run off-grid or replace the inverter with an NRS-certified one.
Many of folks went through that when NERSA forced CoCT to enforce the SA regulations in and around solar panels connected to a DB, in layman’s terms.
Now you know. Your call.
Caveat Emptor