Circuit protection devices are a necessity.

No matter where you may be in the world, the need to ensure that property and life isn’t damaged is paramount.

Given the dynamism of the electrical supply system and its thousands of interacting parts—from step-up to step-down transformers, to conducting materials and wires—faults, short circuits, and overcurrents are fairly common occurrences that cannot be prevented.

However, even though we cannot prevent them, we can make sure these dangerous, higher currents are not borne by our expensive appliances and loved ones through circuit protection devices.

And what are the most common circuit protection devices in the market? You may have heard of fuses and miniature circuit breakers (MCBs). With different mechanisms, they prevent electrical damage emerging from short circuits and overcurrent. This blog post delineates the differences between fuses and MCBs, with their respective advantages and disadvantages.

Speed

In this department, fuses are the superior device. The operating time of a fuse is at an average of 0.002 seconds. The operating time of a miniature circuit breaker is 0.02 – 0.05 seconds. Does this make the fuse the superior device overall? Not necessarily.

Destructibility

Most people, and I am sure that includes you, know that the fuses are a single-use device. Whenever the current exceeds a certain predefined value, the conducting material melts, which breaks the circuit, preventing the dangerous current from moving in further to damage the appliances.

A miniature circuit breaker, on the other hand, will only “trip” when the current exceeds the safe value. This makes the miniature circuit breaker the superior device in this aspect.

Reusability

A miniature circuit breaker takes only a second, a simple flick of a finger, to “untrip.” Replace the MCB switch back into its On position and your circuit will come alive again—although it is advisable to first find out what caused the short circuit or overcurrent; it could be an internal circuitry issue.

Fuses, on the other hand, require a complete replacement of the fuse wire in order to close the circuit after its destruction. This is a dangerous process that takes expertise, so it is advisable to contact a professional electrician to do the job if you do not know the ropes. Again, this is another reason why miniature circuit breakers are superior, and the chief reason they are the device of choice for most residential real estate.

Isolation of Live Points

Miniature circuit breakers are designed in such a way that the wires and live points are safely hidden from a layman. This makes it more difficult for unqualified people to potter around the circuits and get injured.

Whereas, for a fuse, one terminal always is a live point, so replacing it is not safe to the average homeowner. While replacing it, the fuse will always need the practised hands of a professional electrician. This is another point in favor of miniature circuit breakers.

Application

Fuses are a diverse bunch, and there will be several types available at various ratings of voltage and current, catering to the gamut of equipment, from tiny circuitry to heavy-duty industrial engines.

Miniature circuit breakers, on the other hand, are circuit protection devices that function at a lower voltage range. They are primarily used for protection of residential and commercial property where short circuit current ratings do not exceed 15kA. In this aspect, fuses are superior for their usage in heavier industry, although that is offset by their many drawbacks.

Composition & Cost

A miniature circuit breaker uses electromagnetic force generated from a solenoid to power a switch mechanism. In the event of a short circuit, a plunger mechanism interrupts the current flow. In the event of overcurrent, a bimetallic strip does the same. This complexity makes it far more expensive than a fuse. 

Fuses contain a wire usually made up of metallic materials like copper, tin, aluminium, lead, or silver, which melts down in the event of a fault. This mechanism is fairly simple, which is why it comes at a small cost.

However, when taking everything into consideration, and if your market lies in residential, commercial, and low-duty industrial space, it is best if you buy miniature circuit breakers in bulk. For that purpose, an experienced electricals supplier like Precision Electricals can aid you in your objective.