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Look at the faceplate. There should be a 75˚C or 60˚C rating bsed on the temperature rating of the terminals. You have to use the lowest rating shown, ie, if you use 90˚C cable with a 75˚C termination, you have to derate the cable ampacity to a 75˚C.
An example is look at 310.15(B)(16) in the 2011 NEC.
500kcmil cable is good for 430A in this table at 90˚C, if you had to derate to 75˚C, you loose 50 Amps and derate to 380A.
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How much current flows through circuit breaker trip coil?
The trip coil has the whole circuit load amperage flowing through it. Thepurpose of the breaker is to only allow current up to its trip point. That is the only way that the breaker can sense if the current is within the limit rating. If the circuit load amperage becomes greater that the breaker rating it will trip. The trip coil that you refer to is a magnetic trip which senses the magnetic field that surrounds the wire. Breakers also have a thermal trip which senses a heat build up on the current flowing through it. If the breaker is in a high ambient temperature it will lower the rating on the breaker.
How do you decide the rating of a switch for wiring?
Switch rating should match or be greater than the rating for the protecting breaker.
Do circuit breakers trip more easily in humid weather?
Ambient temperature has an effect on the tripping point of a breaker. If a breaker is operating at near capacity the additional ambient temperature will lower the breaker trip set point. As to humidity making the breaker trip easier, the answer is no. Humidity makes the ambient temperature seem hotter that the true temperature is. A standard operating temperature of breakers is from from -5 to 40 degrees C. If the breaker is used at higher temperatures than 40 degree C they have to be de rated, 50 degrees C to 90% and 60 degrees C to 70%. The standard humidity rating of a breaker is 85%. Humidity that is constantly higher than 85% will require a special tropical environment type of breaker that extends the humidity range up to 95%.
Does a hot day trip a circuit breaker?
The ambient temperature does have an effect on the tripping point of a breaker. If a breaker is operating at near capacity the additional ambient temperature will lower the breaker trip set point.
What happens when you plug a 30 amp appliance into a 50 amp breaker?
The appliance works perfectly. If you did it the other way around (50amps on a 30amp breaker, you would be tripping the breaker. Think of it as a mercury thermometer. The circuit breaker is the maximum temperature and the load on that breaker is the mercury. If the load is lower than the max, everything works beautifully. If the load becomes greater than the maximum rating, then things starting popping.
What does 40 C mean on a circuit breaker?
Answer"40 C" means 40 degrees CENTIGRADE temperature rating.The breaker is rated to warm up to this temperature while in use without risk of fire or breakdown. It should not be used in such a way that it exceeds that temperature.Note that wires connected to the breaker must have an equal or higher temperature rating of its insulation. However, when the wire insulation rating is greater than the breaker rating, the wire's capacity must be determined using the breaker's lower temperature rating.For example:If the breaker is 400C and the wire is 400C, the wire capacity would be based on 400CIf the breaker is 400C and the wire is 600C, the wire capacity would be based on 400CIf the breaker is 600C and the wire is 900C, the wire capacity would be based on 600CI don't believe this to be true... The breaker is tested to and calibrated at the 40c rating. (This has more to do with ambient temp. than the way the breaker is being used) In a case where the temp. may exceed this rating you may trip before seeing the current the breaker is rated. The wire is typically rated @ 75c & 90c and the connection point on the breaker or the lug would be rated @ 60cThe above paragraph is correct It is the ambient rating of the breaker calibrated to trip at that temperature set point. In cold climates this has to be watched very closely. On a -20 C day, on breakers that are exposed to the elements, a breaker on the overload portion of the tripping mechanism may not trip until the current reaches one and a half times the handle rating.
Can a200 amp breaker lug handle a?
Handle a "What"?
Can a circuit breaker defect result in the breaker tripping under normal loads?
Yes, also a higher than normal ambient temperature can also de rate the breaker and allow it to trip at less current that its nameplate rating.
Will a circuit breaker give off less amperage?
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.
How much current flows through circuit breaker trip coil?
The trip coil has the whole circuit load amperage flowing through it. Thepurpose of the breaker is to only allow current up to its trip point. That is the only way that the breaker can sense if the current is within the limit rating. If the circuit load amperage becomes greater that the breaker rating it will trip. The trip coil that you refer to is a magnetic trip which senses the magnetic field that surrounds the wire. Breakers also have a thermal trip which senses a heat build up on the current flowing through it. If the breaker is in a high ambient temperature it will lower the rating on the breaker.
How do you decide the rating of a switch for wiring?
Switch rating should match or be greater than the rating for the protecting breaker.
Can you replace a 2000 A Circuit breaker with 3150 A rating?
No.
Do circuit breakers trip more easily in humid weather?
Ambient temperature has an effect on the tripping point of a breaker. If a breaker is operating at near capacity the additional ambient temperature will lower the breaker trip set point. As to humidity making the breaker trip easier, the answer is no. Humidity makes the ambient temperature seem hotter that the true temperature is. A standard operating temperature of breakers is from from -5 to 40 degrees C. If the breaker is used at higher temperatures than 40 degree C they have to be de rated, 50 degrees C to 90% and 60 degrees C to 70%. The standard humidity rating of a breaker is 85%. Humidity that is constantly higher than 85% will require a special tropical environment type of breaker that extends the humidity range up to 95%.
Does a hot day trip a circuit breaker?
The ambient temperature does have an effect on the tripping point of a breaker. If a breaker is operating at near capacity the additional ambient temperature will lower the breaker trip set point.
How does temperature affect power rating of carbon resistors?
Its normal power rating is at room temperature. For a temperature of 75 degrees, halve the rating.
Rating of a 3 pole circuit breaker is the same for each conductor?
Yes, the rating of a 3 pole circuit breaker is the same for each conductor that is connected to it. A three pole breaker rated at 30 amps will have 3 #10 wires from it that connect to the load.
What happens when you plug a 30 amp appliance into a 50 amp breaker?
The appliance works perfectly. If you did it the other way around (50amps on a 30amp breaker, you would be tripping the breaker. Think of it as a mercury thermometer. The circuit breaker is the maximum temperature and the load on that breaker is the mercury. If the load is lower than the max, everything works beautifully. If the load becomes greater than the maximum rating, then things starting popping.
