# 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?

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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.

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It means things that consist mainly of an electric motor, or have a transformer.

Things that are OK:

• Lights
• Laptop / PC
• Kettle (but check that it's not an induction heater one)

Things that are not OK:

• Washing machine
• Vacuum cleaner
• 110v - 240v transformer
• Fridge
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Thank you very much: that clarifies things. I wonder if you could please edit your answer to also mention: 1. Fluorescent lights. 2. Electric fan heaters. 3. What about 1000 W of lights, plus a vacuum cleaner, all together on one branch circuit? –  unforgettableid Mar 30 '12 at 0:30
@unforgettableid, if it has an electric motor in it you cant use this part. If you think it might have an something in the not okay list you need to not use this part. If you start combining sets of appliances you would need to have a good idea of what they consider too inductive, but we are talking about possibly causing a fire, are you really saving that much money to risk it in that situation? –  Kortuk Apr 17 '12 at 2:24
Note that some kettles will be induction heaters, which are highly inductive (as the name implies). That might not be a good example... –  Kevin Vermeer Apr 17 '12 at 4:26
Laptop/PC will have a switching power supply that includes a transformer. –  sharptooth Apr 17 '12 at 12:37
@sharptooth: The problematic transformers are the ones that are large and operate at 60Hz. A 15 amp breaker isn't going to have any problem killing power to a 1W transformer inside an alarm clock, nor will it have problems with a laptop's switching power supply that converts 60Hz to a high frequency before passing it through a transformer. –  supercat Apr 17 '12 at 15:19