Can AC and DC circuit breakers be used interchangeably?

First of all, it must be clarified: AC circuit breakers must not be used to replace DC circuit breakers in DC circuits!

Due to differences in arc generation and extinction processes between AC and DC, AC and DC circuit breakers with the same rated values do not have identical capabilities when interrupting DC power. Using AC circuit breakers in place of DC ones, or mixing AC and DC breakers, is one of the main causes of protection miscoordination and unintended upstream tripping.

Circuit breakers use a thermal-magnetic (electromagnetic) tripping mechanism for instantaneous operation. The key parameter affecting tripping is the peak current flowing through the breaker. The breaker's rated value refers to the RMS (root mean square) value, whereas the peak value of AC current is higher than its RMS value (approximately 1.4 times). Under the same setting, if an AC circuit breaker is used in a DC circuit, its actual tripping current will be higher than that of a DC breaker. When an overload occurs, the local breaker may fail to trip, causing the upstream breaker to trip instead—this is known as "over-level tripping." Additionally, because AC and DC circuit breakers employ different arc-quenching principles, DC arcs are inherently more difficult to extinguish than AC arcs. DC breakers are therefore designed with higher arc-quenching performance requirements. Using an AC circuit breaker in a DC circuit cannot effectively or reliably extinguish the DC arc, which over time will inevitably lead to welding of the main contacts.

From the above, it is clear that AC and DC circuit breakers must not be used interchangeably. Simply put, if AC and DC circuit breakers were truly universal, why would there be a distinction between them at all?