What is discrimination in circuit breakers?

Discrimination is the coordination between the operating characteristics of circuit breakers placed in series. When the fault occurs in system only the circuit breaker placed immediately upstream of the fault will trip.

What is cascading in circuit breaker?

Few Words About Cascading Cascading provides circuit breakers placed downstream of a limiting circuit breaker with an enhanced breaking capacity. Cascading makes it possible to use a circuit-breaker with a breaking capacity lower than the short-circuit current calculated at its installation point.

What is circuit discrimination?

Circuit breaker discrimination (also known as selectivity) is the ability of the local circuit breaker to operate before any upstream circuit breakers under fault conditions. The intention is to limit the service interruption to the minimum amount for any fault, whether this fault is overload or short-circuit.

What are the limitations of circuit breaker?

The metal either melts or it does not. Circuit breakers, on the other hand, could potentially fail if the inner workings prove faulty. Because they react slower than a fuse, appliances and electronics could potentially be damaged. Replacing a fuse requires careful attention to the amperage of the circuit.

What is meant by good circuit discrimination?

3.8.6 – Discrimination. Most installations include a number of protective devices in series, and they must operate correctly relative to each other if healthy circuits are not to be disconnect ed. Discrimination occurs when the protective device nearest to the fault operates, leaving all other circuits working normally …

How do you test for discrimination?

To prove discrimination, a complainant has to prove that:

1. they have a characteristic protected by the Human Rights Code [Code];
2. they experienced an adverse impact with respect to an area protected by the Code; and.
3. the protected characteristic was a factor in the adverse impact.

What is a circuit breaker kA rating?

kA rating of an MCB or an MCCB is the maximum current it can safely interrupt in case of a short circuit. If the current goes beyond this value, the circuit breaker could be damaged. kA rating is known as the short circuit withstand capacity or ultimate breaking capacity of a circuit breaker.

How do you cascade a circuit breaker?

Cascading between 2 devices is normally achieved by using the tripping of the upstream circuit breaker A to help the downstream circuit breaker B to break the current. By principle cascading is in contradiction with selectivity.

Why is electrical Discrimination important?

Discrimination (or selectivity) is the selection of protective devices so that the device nearest to a fault will operate rather than any upstream device. The purpose is to ensure that the fault is isolated and supply is maintained to other parts of the installation without disruption.

What are the advantages of using circuit breaker What can be its limitations?

Circuit-breakers offer the following advantages compared to fuses.

• Circuit-breakers respond quicker than fuses.
• Circuit-breakers are more reliable.
• Circuit-breakers are more sensitive.
• Unlike fuses which only operate once and need to be replaced a circuit-breaker can be reset.

What are the advantages of having a circuit breaker?

Extended protection And under overload conditions, a circuit breaker can trip up to 1000 times faster than a fuse. Some circuit breakers also provide exceptional fault current limitation, a capability previously associated only with fuses.

Why is electrical discrimination important?

What does cascading mean in a circuit breaker?

Cascading refers to the enhanced (reinforced) breaking capacity of the lower device. It has nothing to do with discrimination. It means the lower device can be installed in a location where fault currents are up to 50kA, even if the native breaking capacity is lower than this. Above 36kA, discrimination is not guaranteed.

When does discrimination occur in a circuit breaker?

Discrimination is the coordination between the operating characteristics of circuit breakers placed in series. When the fault occurs in system only the circuit breaker placed immediately upstream of the fault will trip. Discrimination as per IEC 60947-2 can be defined as follows:

Is there a rule of thumb for circuit breakers?

Given that, is there a rule of thumb regarding the gap between the thermal part of the tripping curves of the downstream and upstream circuit breakers to provide good partial discrimination (that is discrimination for current overload). If there is a rule of thumb, I’d like to also know its basis.

Can a thesis be posted on a circuit breaker?

Promoting, selling, recruiting, coursework and thesis posting is forbidden. Hello. I don’t normally deal with this type of things so I am a bit confused with this issue. I have two circuit breakers, the upstream circuit breaker is rated for currents 100A-160A and the downstream circuit breaker is rated for currents up to 25A.