Use of 230VAC overcurrent protection for 24VDC circuits
Is it right to use 230VAC overcurrent protection for 24VDC circuits?


Circuit breakers work by current, not voltage. The voltage rating is the maximum voltage the breaker can safely and dependably interrupt if a short occurs downstream. Normally using a AC breaker in a DC circuit is not a good idea, as the AC breaker is expecting a zero-crossing point at least 100 to 120 times per second. DC current is non-stop and runs the risk of the breaker contacts welding/arc welding together and things going "BOOM". Those who did the 230vac breaker installation are counting on the low voltage DC to not have enough energy to destroy the breaker if a short occurs. If it passed inspection, there must be guidelines I am not aware of and do not have access to.Other issues would be physical space, contact type (to the breaker panel), and if you want a built-in fuse. It is not wrong to use a breaker at a lower voltage than its maximum rating, but it must fit properly to the panel used. Fuses would not fit in the same panel.If you have the option, for your own 24vdc designs I would use the fused version (2nd link) with a built-in 24vdc LED. Using a 230vac breaker seems like a waste of money, even if some test labs use them for 24vdc protection, at their own risk. You paying for your own parts is much different than a company that can throw thousands of dollars or euros into a simple 24vdc power distribution panel. Play it safe and use DC breakers and fuses on DC circuits.