DC Circuit breakers(DC MCB) last a long time so you should check your other options before deciding that issue is a faulty breaker. The breaker may need to be replaced if it trips very easily, doesn't trip when it should, can't be reset, is hot to the touch, or looks or smells burnt.
Will a DC circuit breaker trip due to high voltage (exceeding voltage rating) or will it only trip because of high current? For example, if you have a 40 Amp DC circuit breaker which also has a 32 voltage rating would you have to keep the amperage below 40 and also keep the voltage below 32? Or do you only have to consider the amperage not going above 40?
Yes, very important! Each fuse is marked with a nominal current rating. The current rating of the fuse must be higher than the circuit’s normal operating current. As to how much greater, it depends on a number of factors, including what type of opening characteristic you desire. Please contact FEEO for more specific advice.