What is meant by breaking capacity?

What is meant by breaking capacity?

Breaking capacity or interrupting rating is the current that a fuse, circuit breaker, or other electrical apparatus is able to interrupt without being destroyed or causing an electric arc with unacceptable duration.

What is breaking capacity 10kA?

kA rating is known as the short circuit withstand capacity or ultimate breaking capacity of a circuit breaker. For example, if the MCB is rated at 10kA, it means that the MCB can safely break the circuits during short circuit unless until the short-circuited current does not exceed 10kA.

What is breaking capacity measured in?

This is the connected circuit breaker’s breaking capacity, measured in amperes.

What is the breaking capacity of a protective device?

The effective breaking capacity of overcurrent devices varies widely with their construction. Semi-enclosed fuses are capable of breaking currents of 1 kA to 4 kA depending on their type. whilst cartridge fuses to BS 1361 will safely break at 16.5 kA for type 1 or 33 kA for type II.

How is the breaking capacity specified?

The breaking capacity of a circuit breaker is specified either in terms of symmetrical breaking current/MVA or asymmetrical breaking current/MVA.

What kA rating should I use?

Residential RCDs typically have a fault current rating of 4.5kA, commercial and industrial RCDs must have a fault rating of 6kA or more. kA is essentially the strength of the RCD, so how much ‘fault current’ it can handle. 4.5kA means the RCD can handle 4.5kA of ‘fault current.

What is rated breaking capacity of circuit breaker?

The rated breaking capacity (Icu) or (Icn) is the maximum fault-current a circuit-breaker can successfully interrupt without being damaged. The probability of such a current occurring is extremely low, and in normal circumstances the fault-currents are considerably less than the rated breaking capacity (Icu) of the CB.

Do I need a 6kA or 10kA MCB?

The capability of the MCB to operate under these conditions gives its short circuit rating in kiloamps (kA). In general for consumer units a 6kA fault level is adequate whereas for industrial boards 10kA fault capabilities or above may be required.

What is MCB breaking capacity?

Breaking capacities are measured in kiloamperes (kA), each of which is 1,000 amperes (amps), the standard unit of electrical current. The number of poles or trippable switches within the MCB housing. Pole options include single, double, triple and neutral, and four-pole.

What is breaking capacity of fuse?

> Breaking capacity is the maximum short circuit current a fuse can safely blow without a catastrophic failure such as a fire, breakage or explosion. > Low and high breaking capacity ratings typically range from 35A up to 10kA.

What is 10KA in MCB?

MCB Breaking Capacity: Breaking capacity can be defined as the maximum level of fault current which can be safely cleared. It is written as in numerals like in in example it is 10000. It means it 10000A = 10kA. Choose breaking capacity as per your fault level possible.

Why breaking capacity is important?

It is important to use a breaker that has a high enough breaking capacity to interrupt the maximum possible current and voltage in a system because an unchecked surge in electrical energy can do damage to electronics or to a building.

What does IEC 60947-2 stand for?

Ultimate breaking capacity (Icu) and Service breaking capacity (Ics) – IEC 60947-2 Circuit breakers are devices that can protect circuits or loads during overloads and short circuit. The reliability of the circuit breakers during short circuits is determined by Ultimate breaking capacity (Icu) and Service breaking capacity (Ics) ratings.

What is service breaking capacity of circuit breaker?

Service breaking capacity is the maximum short circuit current the circuit breaker can safely break at least three times and still resume its normal operation. This current can be equal to less than or equal to the ultimate short circuit breaking capacity of the circuit breaker. It is denoted as I cs and rated in kilo-Amperes.

What is the service short circuit breaking capacity (I CS)?

The service short-circuit breaking capacity (I cs) is the breaking capacity according to a specified test sequence that does include the capability of the circuit breaker to carry 85 percent of its nontripping current for a specified time. IEC/EN 60898-1 defines fixed values of the ratio of I cs to I cn.