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Circuit Breaker and Fuse explained | Which is best?

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What you need to know about the Fuse vs Circuit breaker

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Fuse Vs Circuit Breaker

Nothing can replace a human life. You must have heard short and sweet but cautionary words “safety first.” The same “safety first” principle applies here, as the primary purpose of using circuit breaker and fuse in different systems is to provide protection to electrical equipment.

Electrical equipment or I should say electrical control panel; the heart of your home’s electrical system. This panel connects with a line wire coming from the transformer, or the power generation plant.

A question must touch the horses of your imagination; why should you use circuit breakers when the stakes are high – aka high current flow, and when you should use fuse…

You must intend to solve this riddle, — worry not, I’ll guide you through the types of circuit breakers, types of fuses, when to use circuit breakers, and why do they trip.

Why was Circuit breaker invented?

Thomas Edison developed the idea of a circuit breaker in 1879. He realized short circuit and lighting could be dangerous for costly electrical equipment and humans.

He built an industrial laboratory to work on his new invention and later developed the concept of a mechanical device called a circuit breaker.

More subsequently, Granville woods worked day and night on the circuit breaker and came up with an automatic circuit breaker in 1900.

Moreover, Cutter Manufacturing Company was the first company that manufactured the circuit breaker in Philadelphia in 1904.

Different types of circuit breakers and rating

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Circuit Breaker

Industries and home use circuit breakers which are automatically operated electrical switch.

Regarding functionality, the essential function of the circuit breaker is to provide safety from high voltage current exposure to life. Circuit breakers manufactured in different sizes, and in separate current ratings. 

Low current rating circuit breakers are used to protect low-current circuits, and high current rating circuit breakers used in generation plants for safety purposes. 

Various types of circuit breakers are used in the systems according to their needs and their applications.

Here is a chart of circuit breaker types.

Two of the most used circuit breakers in daily life are single pole and double pole circuit breakers.

It consists of one switch, and has one hot wire, and one neutral wire operated at 120v.

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Single Pole Circuit Breaker

In case of 220v there are 2 hot wires, for which two poles are needed to interrupt the two hot wires on fault. Two of their switches are joined together.

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A picture from an electrical panel box where double pole circuit breaker is marked circle.

Miniature circuit breaker (MCB)

  1. Current rating is less than 100A with only one over current protection inbuilt.
  2. The trip settings are not adjustable in MCB.

Standard rating of MCB: 1A, 2A, 3A, 4A, 6A, 10A, 13A, 16A, 20A, 25A, 32A, 40A, 50A, 63A, 100A.

Molded case circuit breaker (MCCB)

  1. Current rating is greater than 1000A.
  2. This has earth fault protection in addition to over current protection.
  3. Trip setting can vary easily.

Standard rating of MCCB: up to 2500A

Circuit breaker symbol

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Symbol of Circuit Breaker

Types of Circuit Breaker

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Types Of Circuit Breaker

Fuses and its types

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Different Types of Fuses

Fuses have been used since early days in electrical engineering, and they are easily available in the market with different ratings. 

Different rating fuses are used with different electrical systems in series – for the protection and safety.

During the short circuit and overload, current will go higher to the rated value so the metallic wire in the fuse wit in millisecond and 

According to Wikipedia, Fuses use as a protection, due to over-current and striking of light these electrical equipment get a lot of current. Fuses provide safety to the electrical equipment.

Fuse symbol

fuse-symbol
Symbol of Fuse

Types of fuses

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Types of Fuses

When to use a fuse vs circuit breaker?

To understand when to use which,

The Circuit breaker is an electrical switch having both electrical components and mechanical parts. It also requires continuous maintenance; they are costly and need a prominent place for installation.

On the other hand, fuses are cost-effective and require less place for installation.

  1. Circuit breakers are used in conditions having immense voltage current and where the chances of system failures are high.
  2. Fuses are cost-effective, and we use in electrical circuits where we have meager chances of component failure.

Why do circuit breaker trip

Circuit breakers and fuses are use to cut off the electricity flow and to protect the circuit from overheating. If your circuit breakers are constantly tripping, then you need to find the cause behind it. Well, there are three main reasons why circuit breaker trips and fuses blow:

  1. Overloaded Circuit
  2. Short circuit
  3. Ground fault

Tripping a circuit breaker could be a reason for the overloaded circuit. You might have installed a new appliance, and the load increases on the existing circuit.

As the load increases and extends the certain threshold level, the internal mechanism of a circuit breaker will heat-up, resulting in breaking the contact. Current will not flow again until someone manually put a lever in an ON mode.

The demand, or load, on the circuit is high. Tripping a circuit breaker suppresses the circuit from overheating. If you don’t use circuit breaker you might end up burning you equipment.

overloaded-circuit
If you don't use circuit breaker you might end up burning in your circuit or equipment.

You might not know what a short circuit is, as the name suggests, “short,” when two conductors supplying electrical power to any circuit and a low resistance wire comes in between. It makes the current flow through the shortest path; it causes heat to the circuit, and eventually ends up burning the circuit.

When a hot wire touches another hot wire or neutral wire, it flows a larger amount of current and heat than the circuit could handle.

What causes a short circuit?

  1. Faulty insulation
  2. Loose connection

It is the same as a short circuit; a ground fault happens when a hot wire touches the ground wire. So it will end up tripping your circuit breaker.

Key differences between electrical fuses and circuit breakers

 

Circuit breaker

Fuse

Definition

It is designed to protect an electrical circuit from faulty current and an excessive current.

It provides protection to electrical equipment from over current.

Advantages and disadvantages

No replacement is required.

Replacement is required after every operation.

Cost

It depends upon the application.

Cheapest

Replacement It can be reused many times. It cannot be reused.

Operating time

As compared to fuses, operating time is little high like 0.1 seconds to 0.2 seconds.

Fuse operating time is very low like 0.001 seconds to 0.002 seconds

Applications

Miniature circuit breakers are used to protect the electrical panel.

Laptops
LCD monitors
Battery packs
Cell phones

Functions

Basic function of a circuit breaker is to break the contact in between when any faulty current occurs.

Fuse is used for over-current protection and its main function is to break the contact when any over-current occurs in the circuit.

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