I have been using CBI D curve breaker for machines ... pump motors ... aircon etc type applications for many many years.

What I dont understand is why they dont work on new inverter type aircons and why we are having so many recalls for a buzzing sound in the DB when the aircon is operating on the new type aircons even if they are not inverter type breakers.

The most recent was an aircon operating at 12 amps, with the compressor running, connected to a 25 amp D curve 6 ka. these breaker should be able to operate up to at least 18/19 amps under full load.

I have had the odd couple fail over the years but noticed with the newer type aircons (not even inverter units) they seem have become a nuisance having to go back to site to replace.