What role do circuit protection devices have in the electrical engineering world? As a safeguard against potential hazards, they help reduce the risk of injury by deliberately including a “weak link” in the circuit. In the event of a fault, this link will break to shield the overall circuit from damage.
Why is Circuit Protection Needed?
Under fault conditions, circuit protection devices prevent high fault currents from flowing. This helps to safeguard both the installed electrical components, and the individuals from harm. This added protection makes circuit protection devices a cost-effective part of electrical installations as they reduce the amount spent on replacement products. Additionally, by automatically disconnecting the power supply, you lower the risk of electrical accidents, injuries, and fatalities.
The requirements and regulations for electrical installations are stringent, and the ramifications of non-compliance can be severe. In the event of an incident, if electrical installations are found to be at fault due to non-compliance, the responsible parties could face serious legal action.
Understanding Circuit Overloads
Understanding the function and characteristics of circuit protection devices, such as fuses and circuit breakers, is essential for ensuring the safety of installed electrical systems. Knowing how circuit overloads occur, and thus how to prevent them, is a key part of knowing how circuit protection devices work.
What Causes a Circuit Overload? 
Circuit overloads occur when the current in a circuit exceeds its capacity. There is more electricity and power introduced than the circuit is designed to handle. These can be caused due to the operation of multiple high-power appliances, or faulty wiring connections upon installation.
Additionally, circuit overloads also pose a potential fire hazard due to possible overheating. This means that a lack of quality circuit protection devices can cause damage not only to the connected electrical components, but the overall structure they are insured in. Replacing degraded equipment is one thing and can be costly, but being liable for an entire building is a different expense all together.
Regardless, prolonged overloading will inevitably lead to equipment degradation, impacting both performance and lifespan. In turn, this will necessitate costly repairs and replacements.
Types of Circuit Protection Devices
Fuses
One of the most traditional types of circuit protection devices, fuses are a simple concept. Using a low-resistance piece of metal wire in a circuit, the fuse will “blow” when overloaded to disconnect the circuit. However, fuses are mostly an outdated circuit protection device, with more modern alternative now available.
Miniature Circuit Breakers (MCB)
Like many circuit protection devices, an MCB is used to safeguard a circuit when an excessive current runs through it. Featuring a switch that is designed to move once a circuit is tripped. As a result, the flow of electricity will be disrupted. Unlike fuses, once a fault is cleared, an MCB can be simply switched back to their “on” position which removes the need for constant replacements.
You will often see multiple MCBs fitted into a power distribution box, which protect the different circuits in a building. This means if one circuit is overloaded, the MCB will not shut off the other circuits which will ensure electricity still flows through the rest of the circuits.
Residual Current Devices (RCD)
RCDs constantly monitors the flow of electricity in a circuit and automatically shuts off the current if there is any abnormality detected. Additionally, RCDs can be used to protect more than one circuit at a time but if they shut down power, they do so for them all which can introduce nuisance and hazards for the user.
Basically, an RCD is in place to protect the user, whereas an MCB is designed to protect the circuit.
Residual Current Breaker with Overload Protection (RCBO)
Combining the functionality of an RCB and an MCB, this type of circuit protection device features a combined protection for the user and the installation. This higher level of protection against earth leakage faults, overloads, and short circuits makes them ideal for both domestic and commercial environments where electrical safety and versatility is crucial. In the event of a fault being detected the RCBO will isolate the circuit but leave other healthy circuits operational within the consumer unit.
Conclusion
Circuit protection devices are crucial for electrical system design and maintenance. They offer essential safeguards against potential fire and electrical hazards, and any contractor or business can find themselves liable if they do not install effective safety equipment. Circuit protection devices are important because they:
- Allow compliance with safety regulations.
- Mitigate risks to ensure the continued safety of electrical equipment.
- Minimise the risk of injury to both installers and end users.
Understanding what can cause damage to existing circuits and electrical systems is key to ensuring you comply with the stringent regulations that are in place. Protecting the installation and system is important, but these devices are required to ensure consumers are not injured (or even killed) because of an electrical fault. Quality circuit protection devices are a crucial component to help ensure the safety of all users and installers.
For those looking for high-quality circuit protection devices, visit the Deta Electrical website to browse our range of products by clicking here.