What breakers are there to protect is the cable in your wall.
The cable should be rated to run at 100% load continuously (with some safety factor for running a little more); depending on the breaker rating and curve (usually C curve in New Zealand for domestic).
So a C20 breaker can supply 120A for 1s before protecting the circuit; this allows for starting motors.
Now a breaker is different from an RCD which measures the difference between the phase and neutral lines. If the difference is too high the circuit trips. This is to protect the fleshy thing holding the knife in the toaster.
In America, they always say that continuous loads should run at 80%. That’s why circuit breakers are specced at 15/20/30/40/50/60 amp but the EVSE is specced at 12/16/24/32/40/48 amp.
What breakers are there to protect is the cable in your wall.
The cable should be rated to run at 100% load continuously (with some safety factor for running a little more); depending on the breaker rating and curve (usually C curve in New Zealand for domestic).
So a C20 breaker can supply 120A for 1s before protecting the circuit; this allows for starting motors.
Now a breaker is different from an RCD which measures the difference between the phase and neutral lines. If the difference is too high the circuit trips. This is to protect the fleshy thing holding the knife in the toaster.
In America, they always say that continuous loads should run at 80%. That’s why circuit breakers are specced at 15/20/30/40/50/60 amp but the EVSE is specced at 12/16/24/32/40/48 amp.
Aye. US NEC says 80% is safe carrying capacity. There is an expectation there will be surges or dirty power that might take it a little