If you pay attention to the circuit breakers at your home, office, or industrial sites, you must have come across two terms, RCCB and MCB.
An overall power circuit includes wires, fuses, circuit breakers, sockets and other appliances. RCCB and MCB are two types of circuit breakers placed here. They protect your home and the people living there from any hazards caused by any irregular current flow.
While both of them are circuit breakers, some factors make them different. To understand your power supply at home or office properly, you should learn the differences.
In this article, we will talk about what they are, and the major differences between RCCB and MCB, while also discussing which needs to be connected first.
What is an MCB?
MCB or Miniature Circuit Breaker is a voltage-sensing device. It breaks the circuit during a short circuit or an overload. Such issues generate a huge amount of current and can cause damage if not taken care of appropriately.
MCB helps to prevent that by tripping off. Anyways, for short circuits, the trip is an immediate occurrence. For overloads, it takes a few seconds to trip.
What is an RCCB?
RCCB or Residual Current Circuit Breaker is a current-sensing safety measure. It breaks the circuits when it senses a current leakage. Thus, it ensures protection against electric shocks.
When a person comes in contact with a current-carrying conductor, the current in the electrical circuit is branched. then a current leakage takes place. An RCCB can control an imbalance in current by tripping within 20 milliseconds.
MCB vs RCCB: The Key Differences
Both MCBs and RCCBs are circuit breakers are designed with the same purpose—protecting against electrical hazards. But their unique features and roles make them different from each other. Let’s see what the differences are.
- The main difference lies in their roles. An MCB protects against overloads and short circuits. An RCCB is mainly used for protection against earth leakage.
- MCB costs less than an RCCB. Many times, due to the high cost of RCCB, people opt for only installing MCB.
- RCCB comes with earth fault protection which MCB does not have.
- On the other hand, MCB has short circuit and overload protection, which RCCB doesn’t have.
- An RCCB’s sensitivity is less than that of an MCB.
- In an RCCB, only two poles or 4 poles can be there. The number of poles available in an MCB is 1, 2, 3, and 4.
- An MCB is applied in local control switches, protection circuits, and fuse alternatives. An RCCB is used to prevent major electrical failures and protect against direct or indirect contact.
- In an MCB, you cannot run a test operation. But this option is available in an RCCB. You can check the RCCB’s working condition using the ‘T’ button.
- The rating for an MCB is 63A full load current. It is 63A full load current and 30-300 mA earth leakage current for an RCCB.
- MCB cannot protect human beings against shock. An RCCB can do it well.
RCCB vs MCB: Manufacturing components
Besides the differences in application and features, RCCB and MCB are different in their components as well.
An MCB includes an incoming terminal, magnetic coil, bimetal strip, arc chute, copper braid, operator ON/OFF handle etc. Along with them, it has a core body.
An RCCB has a CBCT or Core Balanced Current Transformer. It also comprises a magnetic relay coil and incoming and outgoing terminals with a tripping mechanism.
MCB works with a thermal overload protection principle. When excess current flows in the circuit, the temperature increases. As a result, a trip occurs.
An RCCB works on the principle of Kirchhoff’s law. The law says that the incoming and outgoing current flows in a circuit should be equal.
In other words, the neutral and phase current should be the same. When due to a fault, the phase current becomes higher than the other one, an imbalance in current takes place. An RCCB detects it and trips.
MCB or RCCB: How They Should be Connected
Usually, MCB and RCCB are installed jointly in a circuit. The purpose is to protect the circuit from short circuits, overload and earth faults.
The MCB should connect before an RCCB connection. if you connect MCB after RCCB, both of them cannot detect any fault occurring between these two circuits.
Final Words
In earlier times, there was only MCB. So, people had no option but to choose it. But, nowadays, when you have another advanced device, you should opt for it too. After all, the more protection you ensure, the safer you can feel. So, what are you waiting for? Buy and install MCB and RCCB now to protect your electric circuits from any damage. Visit L&T-SuFin to check out some excellent choices on offer.