Requirements for noise levels of transformers?

     The relevant regulations of the state on the noise of transformers in great detail. Regarding the question about the noise of transformers, the experts explained that the transformers will announce a kind of "buzzing" electromagnetic static in operation, but the impact on the surrounding environment is simply very small. In accordance with the relevant national norms, usually residential noise requirements of less than 55 DB. Therefore, as long as the residential area transformer noise is not more than 55 DB, it will not affect the normal day.