Electronic – Cooper Bussmann’s screw-in Edison-base mini breakers aren’t for inductive loads. What does “inductive” mean


I'm thinking of buying some Edison-base screw-in miniature circuit breakers to replace some of the fuses in my house. There are some made by Connecticut Electric and some made by Cooper Bussmann.

Cooper Bussmann writes that their Edison-base mini breakers aren't for inductive loads. I don't know too much about electricity. What does "inductive" mean?

Best Answer

The simple answer is: Don't risk it and get ones that are rated for inductive loads. Here's the relevant Wikipedia article on power factor. Basically you have electrical impedance which consists of electrical resistance (which is opposition to movement of current created by resistors) and reactance (which is opposition to movement of current by all kinds of coils and by capacitors). In DC systems, the reactance is zero.

Actual reactance depends very much on the circuit itself and it can be zero and then we say that the circuit is resistive, it can be greater than zero and we say that the circuit is inductive and if it's lower than zero, we say that circuit is capacitive. By adding capacitors to inductive circuit we can make it less inductive, resistive and, if we add enough capacitors, capacitive. Same goes for other way around. If we add enough coils to capacitive circuit in the end we can get inductive circuit.

The problem here is that it's not uncommon to find device that doesn't provide enough data to easily determine if it's capacitive or inductive, what its power factor is and it can be difficult even when all that is known to calculate if the total load on the circuit breaker is resistive, capacitive or inductive. Another point is that the circuit-breakers linked don't provide (or at least I can't find) enough information to determine when an inductive load is too inductive for them.

So to be safe, just get circuit-breakers that can break an inductive load.