A circuit breaker does not give off amperage. A circuit breaker allows a flow of current up to the rating of the breaker. Any current higher than that of the breaker's rating will open the breaker's contacts and stop the flow of current.
Yes. A twenty amp circuit just means the breaker (fuse) will kick in if you draw more then 20 amps, but its fine to use at less amperage.
The purpose of a circuit breaker in a panel is to protect the wiring and devices like switches, outlets and other devices that are part of that circuit. It isn't unusual to plug in an appliance into a circuit whose amperage rating is less than the breaker protection. If such an appliance doesn't have its own over-current protection it may well "fry" in an over current situation. However, if your 40 Amp device is directly connect to the 70 A circuit and has no over-current protection on its own you are risking a serious problem. If your 40 A device is on this dedicated circuit you should protect it with a properly sized breaker.
No. The breaker must protect the circuit components such as wiring, outlets and switches that are connected to the breaker. Therefore if you have a 30 amp circuit as dictated by its components you need to protect it with a 30 amp or less breaker.
The previous answer is incorrect, and I would advise that user to not give out information if they are going to give completely misguided information. The interrupting rating of a breaker is the maximum current that the breaker is designed to handle, at the breaker's rated voltage, before damage will occur to the breaker. A breaker will trip at FAR LESS than the interrupting rating, but it is extremely dangerous to expose the breaker to any situation where it will have more than the rated interruption current. the breaker is designed for. The reason some breakers are rated at 22kA instead of 10kA is because they typically have far larger conductors hooked up to them, so with the lowered impedance on the circuit there is more of a chance for the breaker to experience a higher fault current at the breaker. So electricians install 22kA breakers to handle the higher "available fault current."
No, all it will do is make the circuit unsafe if a larger breaker is installed or make the circuit trip unnecessarily if a smaller breaker is installed. You pay for the wattage that you use. Less wattage used, less cost on your utility bill.
Miniature circuit breakers are smaller & easier to instal. It occupy less space & are more efficient
Check and see what the amperage the A/C unit draws. These types of appliances should have their own dedicated circuit. If there is nothing of a high load on the existing 120 volt circuit and the A/C unit draws less than 12 amps, the unit should operate without tripping the breaker. If the A/C unit only has wattage and no amperage shown on the nameplate use this equation to find the amperage. I = W/E, Amps = Watts/Volts.
For the lighting load the amperage is A = W/V = 600/120 = 5 amps. As for what will be plugged into the receptacles will be a guess for the calculations. I will give you a full 15 amps for receptacle loads at 120 volts. Total amperage is 20 amps. The breaker for this circuit will be a 20 amp breaker but there may be a problem getting the #6 wire under the breakers terminal connection points. If this is the case use a #6 lug to connect to the breaker and connect the wire into the lug. A #6 copper conductor will limit the voltage drop to 3% or less when supplying 20 amps for 200 feet on a 120 volt system.
To correctly size a lighting circuit, you must know the total power that the circuit will draw, in watts. For example, if there is 7 lights on a circuit, each light consumes 100W, that gives you a total of 700W on the circuit. Then you must know the voltage that is being supplied to the circuit. For this example, 120VAC will be used. To calculate the current needs for sizing the breaker, use the formula P=E*I, where P=watts, E=voltage, I=current/amps. So, in this example, P=700, E=120, I is unknown. After working the formula, you have an answer of 5.83 A. Breakers generally come in sizing increments of 5A.....5A, 10A, 15A, 20A, etc. The answer for this example was 5.83A, so the 5A breaker is obviously not enough. The next size is 10A, which is more than the calculation, but you must also consider that breakers are designed to operate at 80% capacity for periods of time over about 3 hours. So for an office atmosphere where the lights will definitely be on for longer periods of time than residential (in most cases), you would need to make sure that the total Amps needed is equal to or less than the 80% of the breaker size you have chosen. A 10A breaker is only designed to provide 8A of capacity for longer periods of time. So for this example, a 10A circuit breaker would be properly sized. You must also abide by the NEC code for maximum number of fixtures on any particular circuit. Refer to NEC for that information. If you were to change the light fixtures to a larger size, such as 200W each, you would then find that you need to also change the breaker and possibly the wire size that is run through the circuit, to maintain compliance with NEC.
Answer for countries in Europe and other world areas running a 50 Hz supply service.Depending on the load of your lighting circuit. I would measure the current with an inductive amp meter. once you know the current required for your lighting circuit, you then install a circuit breaker which is 15% higher than your load. eg, load is 10A. 10A load + 15 % = 12A breaker (15 A is ok as the breaker is used to protect the wiring and should be rated in consequence of your wiring by 25% less or its current rating, or less, not the load)The humming of your lighting circuit breaker indicates that your breaker is either faulty, or having a difficult time keeping a closed circuit. Or simply that the manufacturer produced a breaker that hums by nature of its construction.
Depends on what you have connected to the circuit. It is less than 10 amps or the breaker would trip. A rule of thumb is you design for about 80% load related to the breaker. For 20 amps that would equal 16 amps.
A 40A MCB is a circuit breaker. The surge current limit is protected to 250A 8/s0uS. The limitation capability of a circuit breaker is that characteristic whereby a current less then the prospective fault current is allowed to flow under short circuit conditions.