MCB installation guide for home and office

Miniature circuit breakers are commonly used in electrical systems nowadays. MCBs are categorised as electronic safety devices which protect your equipment and personnel from power surges. You can read our blog about how MCBs have replaced fuses over the years to understand the advent of these devices in modern electrical systems. Now, since miniature circuit breakers play such an important role in home and office electrification, proper installation of MCBs is quite critical.

In today's post we present a comprehensive guide to installing an MCB, right from the selection of an MCB to wiring it correctly and safely.

Step 1: Selecting the right MCB

MCBs vary by poles, voltage, and current capacity. Selecting the right MCB requires technical knowledge and hiring a professional to do the installation is the best way forward for home and business owners. Even if you have a basic understanding of electrical setups, you may lack the tools necessary for safe and correct installation. Thus, we recommend consulting an electrician in choosing the right MCB for your electrical layout.

Step 2: Buying MCB online or offline

Once you know which type of MCB is needed, the next step is to select a reliable brand and vendor. Branded MCBs are always recommended over locally manufactured products, as it concerns the safety of your family, personnel, and equipment. Branded electrical products follow the BIS and international safety standards and are covered by warranty.

If you are setting up a new home or office premise, the best option is to buy electrical products in bulk, to save on cost and transit times. You can also get best price deals when bulk buying MCBs and other electrical products. For example, the Lauritz Knudsen (Formerly L&T Switchgear) offers genuine electrical products and accessories for individual and wholesale orders, just in case you are looking for MCBs online.

If your electrical system is old, and you need to install or replace just one or a few circuit breakers, then it's better to buy from a trusted dealer near you, to save time and fulfil the immediate requirement.

Step 3: Wiring the MCB 

Where a single circuit breaker replacement or installation is needed, the wiring of MCB is very simple.

First, disconnect the main circuit through the isolator switch. Next, remove the panel cover of the distribution board (DB) and securely slot the MCB into position. Use a wire stripper to prepare the ends of the live (red or brown in colour) and neutral (blue or black in colour) wires. Connect the live wire to the live terminal on the MCB and the neutral wire to the neutral bar on the board and torque the screws till they are tight and secure.

Replace the DB cover and reconnect the circuit.

Step 4: Testing 

Switch on the MCB.

If the power comes back and all things work without any sparking, hissing, or flickering, then the circuit is working perfectly. You can also use a voltage tester to check the current flow.

In case there is an issue, disconnect the circuit, and check again for any wiring faults or earthing issues. Better yet, ask a professional to do the installation and wiring for you.

Step 5: Labelling and documentation

Because of the complexity of the modern electrical systems, it is always a good practice to label and document any electrical changes for future reference. Maintaining a circuit diagram of your home or business is also recommended to ensure proper troubleshooting, if and when an electrical fault occurs.

Also Read: What Is The Difference Between MCB, MCCB, DB, RCB, RCD, RCCB, RCBO, And ELCB Breakers

Frequently Asked Questions (FAQs):

1. How to choose the right MCB for my house?

Calculate the total connected load for your household, i.e. the number of fans, lights, air conditioners, and other electrical appliances that are regularly in use. Identify the circuits to be protected by the MCB and proceed to buy a circuit breaker that matches the amperage rating and circuit type. As mentioned earlier in the article, consulting a professional electrician is the best way to select the right MCB for your house or office.

2. Can I install multiple MCBs in my house?

Yes, it is possible and is generally done. Modern electrical setups use circuits to distribute the electrical loads efficiently. So, you have different circuits for different areas in the house, and each one requires a separate circuit breaker for protection.

3. What to do if the MCB keeps tripping frequently?

A frequently tripping MCB indicates an electrical issue. It requires professional diagnosis. You can self test the issue by unplugging appliances one by one to identify any faulty equipment. If the problem persists, hire an electrician for a full system check and repair.

4. Can I install an MCB without professional help?

Yes, MCBs can be installed without professional help if you know your way around electrical setups and are willing to do a little DIY repair. However, since modern electrical systems have become complex to manage, we always recommend hiring a professional to do the job safely.

5. How often should MCBs be replaced?

There is no periodic MCB replacement required. You only need to replace an MCB that is burned out or otherwise faulty. Normally an MCB would last for years and even a lifetime if there are no major faults in the system. You can check our MCB maintenance guide to keep your electrical system running smoothly.

6. Can we upgrade MCBs for additional safety?

Yes, MCBs are upgradable. Your existing MCBs can last a long time if there is no major change in the total load. But if you are routinely upgrading your equipment, then it's a good idea to upgrade your MCBs to higher current rating and load capacity.