rcd and circuit breaker

RCD & Circuit Breaker

Electrical safety is crucial for every home and business, and devices like an RCD and circuit breaker are essential in preventing fires, equipment damage, and even electrocution. While both are designed to enhance safety, they operate differently by detecting specific types of faults and cutting the power supply to circuits when needed.

At P Herman & Co, we pride ourselves on being Perth’s trusted electricians, delivering reliable and professional services to homes across the region. Ensuring electrical safety is one of the most important responsibilities for any homeowner, as it protects both your loved ones and your property from potential hazards. That’s why it’s important to have an understanding of RCDs and circuit breakers.

What Is an RCD?

rcd circuit breaker An RCD (Residual Current Device) is a specialised circuit breaker designed to monitor the flow of electrical current in a circuit. It compares the current flowing through the live (hot) wire with the current returning through the neutral wire. Under normal conditions, these currents are equal. However, if some of the current escapes through an unintended path—such as leaking to the earth or passing through a person who has suffered an electric shock—the imbalance will be detected by the RCD.

Sometimes referred to as a safety switch, an RCD is highly sensitive and constantly monitors for even the smallest discrepancy in the current. When the difference reaches as little as 30 milliamps, the RCD immediately trips the circuit, disconnecting the power. This rapid response is crucial in preventing electrocution, as it stops the flow of electricity that could be harmful or even fatal.

RCDs are especially important in wet areas, such as kitchens, bathrooms, and outdoor spaces, where the risk of electrical leakage is higher. They serve as a critical safeguard by ensuring that, in the event of a fault, the electricity supply is cut off almost instantly.

If you’re having trouble with electricity that keeps tripping, we have prepared a guide to explain exactly what is going on, and simple things you can do if your power keeps tripping.
In Western Australia, RCDs are legally required in all homes, particularly in circuits that power outlets in areas where water and electricity may come into contact. This regulation helps protect people from the risk of electric shocks and ensures electrical safety in homes across the state.

What Is a Circuit Breaker?

circut breaker A circuit breaker is an automatic electrical switch designed to protect an electrical circuit from excess current, preventing overheating and damage to wires and other components due to overloads or short circuits. When there’s too much current flowing through the circuit, the circuit breaker is triggered to disconnect the power and stop further damage.

Inside a circuit breaker, there’s a strip or wire made from two metals that expand and bend when heated. When the current exceeds a safe limit, the strip heats up, causing it to bend and activate a mechanism that trips the switch and disconnects the power. The amount of current needed to trip a circuit breaker depends on its amp rating, with a standard 15-amp circuit breaker typically tripping at around 135% of its rating (approximately 18 amps).

Circuit breakers generally trip more slowly than RCDs. It may take several seconds for the metal strip inside the circuit breaker to heat up and bend sufficiently to activate the trip mechanism. In comparison, RCDs are much faster, cutting power almost instantly when even a slight current imbalance is detected.

While circuit breakers provide critical protection by preventing overheating and property damage, they don’t monitor for leakage currents or protect against electric shocks. Their primary purpose is to safeguard your home’s electrical system from damage due to overloads or short circuits, rather than protecting people from electrocution.

In contrast, RCDs focus on protecting individuals by detecting electrical leaks that could lead to shocks, making them a vital part of your home’s overall safety system. Together, circuit breakers and RCDs offer a comprehensive layer of protection, ensuring both property and personal safety.

“Is a Circuit Breaker the Same as a Safety Switch?”

A circuit breaker is not the same as a safety switch (RCD), though both serve important safety functions in an electrical system.

  • Circuit Breaker:

A circuit breaker is designed to protect electrical circuits from damage caused by overloads or short circuits. When the current exceeds a safe level, the circuit breaker automatically trips to disconnect the power, preventing overheating, potential fires, and damage to electrical equipment. It does not protect against electrocution or leakage of electrical current.

  • Safety Switch (RCD):

A safety switch, or RCD (Residual Current Device), is designed to protect people from electric shocks by detecting any leakage of current, such as when electricity flows through water or a person. When the RCD detects an imbalance in the current, it immediately cuts the power to prevent electrocution, typically at much lower levels of current than a circuit breaker would respond to.

So, while both are critical for electrical safety, a circuit breaker protects against overloads and short circuits, while a safety switch (RCD) protects against electric shocks. In modern electrical systems, both are essential for comprehensive safety.

RCDs Vs Circuit Breakers

rcd vs circuit breakerRCDs and circuit breakers both protect your electrical system, but they function in different ways. RCDs continuously monitor the current on the live and neutral wires, detecting even small imbalances that indicate leakage currents. This allows them to trip rapidly—often at as low as 30mA—to prevent electrocution. In contrast, circuit breakers do not monitor for leakage currents; instead, they trip when the current exceeds a certain threshold, such as during overloads or short circuits, which can damage wires or appliances. While circuit breakers protect property by preventing overheating and fires, RCDs focus on protecting people by preventing electric shocks.

RCDs are incredibly fast, tripping in as little as 0.03 seconds to cut off dangerous currents, while circuit breakers are slower, relying on a mechanical process that can take several seconds to trip, which is sufficient to prevent fires but too slow to stop electrocution. Additionally, RCDs typically require manual resetting after tripping, ensuring the electrical system is checked, while circuit breakers automatically reset once the overload or fault is cleared, allowing power to resume without intervention.

Feature RCD (Residual Current Device) Circuit Breaker
Protection Type Protects people from electrocution by detecting leakage currents. Protects property from overloads or short circuits that can cause fires or equipment damage.
Triggers Detects current leakage to earth or through a person. Triggers when there’s an overload or short circuit in the electrical system.
Installation Requirements Required in all modern homes, especially for outlets in wet areas (kitchens, bathrooms, etc.). Required for safety in most modern homes to protect circuits from overloads and short circuits.

Both devices are essential in maintaining electrical safety, with RCDs focusing on safeguarding people and circuit breakers protecting property. Together, they provide a well-rounded solution to electrical safety in the home.

Why You Need RCDs and Circuit Breakers

RCDs and circuit breakers serve complementary roles in your home’s electrical safety system, offering complete protection for both people and property. While each device is crucial on its own, together they provide a robust solution to electrical hazards.

difference between rcd and circuit breaker RCDs focus on protecting people by detecting small current imbalances that could lead to electrocution. For example, if someone touches a faulty appliance or an exposed wire, the RCD quickly trips, cutting the power and preventing potential injury or death. However, an RCD doesn’t protect against electrical overloads or short circuits, which is where the circuit breaker comes in.

Circuit breakers are designed to protect your home and appliances from electrical damage. They trip when there’s an overload or short circuit, which could otherwise cause fires or damage the wiring. For instance, if you plug in too many devices and cause an overload, the circuit breaker will trip to prevent damage. However, if someone suffers an electric shock due to a current leak, the circuit breaker won’t respond, but the RCD will.

By having both an RCD and a circuit breaker in place, you ensure that your home is fully protected from electrical hazards—whether that’s protecting your loved ones from shocks or preventing fires and damage to your electrical system. Together, they provide a well-rounded defense, addressing both personal and property safety needs.

Legal Requirements in Perth with RCDs and Circuit Breakers

In Western Australia, the installation of RCDs (Residual Current Devices) is a legal requirement in all residential properties, including rental homes. According to the Electricity (Licensing) Regulations 1991, RCDs must be installed for circuits that supply power to outlets in areas where the risk of electric shock is higher, such as kitchens, bathrooms, laundries, and outdoor areas. This regulation is in place to ensure the safety of residents and prevent electrical accidents, particularly in environments where moisture and electricity are in close proximity.

residual circuit current breaker For rental properties, landlords are legally obligated to ensure that RCDs are installed and maintained. This requirement protects tenants from the risks of electrocution and demonstrates a commitment to providing a safe living environment. Homeowners must also comply with these regulations to meet safety standards and avoid potential penalties.

Complying with these legal requirements not only ensures the safety of those living in the property but also protects property owners from liability in the event of an electrical accident. By investing in the installation of RCDs, landlords and homeowners can have peace of mind knowing they are meeting safety regulations and fulfilling their responsibility to safeguard their tenants and families.

How P Herman & Co Can Help

At P Herman & Co, we specialise in the installation, testing, and maintenance of RCDs and circuit breakers, ensuring your home is equipped with the best electrical safety solutions. Our experienced electricians are trained to assess your electrical system, recommend the right devices for your needs, and install them to the highest standards. We also offer comprehensive testing and regular maintenance to ensure that your RCDs and circuit breakers are functioning correctly and providing reliable protection.

We are committed to offering transparent, upfront quotes with no hidden fees, and we pride ourselves on delivering professional and efficient service. Whether you’re installing new safety devices, upgrading your existing ones, or need a safety check to ensure compliance with local regulations, P Herman & Co is here to help.

Book a safety check with P Herman & Co today and take the first step toward ensuring the safety of your home and family!

Frequently Ased Questions About RCDs and Circuit Breakers

How often should RCDs be tested?

RCDs should be tested at least every 6 months to ensure they are functioning properly. This can be done by pressing the test button on the device, which simulates a fault to verify that it trips correctly. Regular testing is crucial for maintaining electrical safety in your home.

What are the signs of a faulty circuit breaker?

Signs of a faulty circuit breaker can include:

  • Frequent tripping of the breaker without an apparent cause.
  • Burning smells or discolouration around the breaker.
  • A breaker that won’t reset, or one that doesn’t trip when it should. If you notice any of these signs, it’s important to have a licensed electrician inspect and replace the breaker as needed to prevent electrical hazards
Can I upgrade my home’s electrical system to meet current safety standards?

Yes, it’s possible and often recommended to upgrade your home’s electrical system to meet the latest safety standards. This may involve installing additional RCDs, upgrading your circuit breakers, or enhancing other components of your electrical system to improve safety and compliance with regulations. We can assess your current system and advise on the best solutions to ensure it complies with safety standards.

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