Circuit breakers are electrical components designed to protect us against the risks of electric shock and our homes against fire and other types of damage that can be caused by electrical failures. Each circuit breaker on your electrical panel generally protects one or more related circuits from overload, short circuit, and earth leakage.
To understand what causes a circuit breaker to explode (or more commonly known as a trip), we must first understand what a circuit is and what the terms overload, short circuit, and earth leakage mean.
What are the circuits?
The electrical installations in our homes are divided into electrically separated segments known as circuits. Each circuit provides electricity to the teams in a very well defined and specific group. All accessories and light switches are on a circuit known as a lighting circuit. The air conditioning, heating and ventilation equipment is grouped into another circuit known as the HVAC circuit. And last but not least, the outlets are grouped together into a circuit known as a power circuit.
Each circuit consists of cables, switches, connections, and other electrical equipment designed to carry only the manufacturer's specified maximum electrical current. When exposed to a current that exceeds this maximum, the electrical component can break, melt, or catch fire. Circuit breakers were introduced to ensure this does not happen by disconnecting the electricity supply when the flowing electrical current exceeds the maximum capacity that the circuit components can handle.
Overloaded circuits: The main reason a circuit breaker trips
Take a look at your home on all the outlets. How many appliances are plugged into each outlet? You probably have more than what the circuit is designed for. Our increasing use of electrical and electronic devices puts more pressure on our electrical installations every day, sometimes to the point where the amount of electricity we use exceeds the amount the circuit can provide us without overheating or damage. When this occurs, the circuit breaker on your board will disconnect the circuit from the electrical supply.
Short circuits: when things really go wrong
Whether you're digging in the garden looking for the big new flower box, or drilling a hole in the wall to place that beautiful family photo, every time you make changes to the house you risk damaging the hidden electrical wires behind from the walls or into the ground. When you drill a hole through a cable or cut it with a shovel, direct contact occurs between the individual cables in the cable. This is known as a short circuit. Electric cables are not designed to withstand current flowing in a short circuit situation. In cases like this, the short circuit protection mechanism in the circuit breaker turns off the power supply to ensure that the cable does not melt or catch fire.
Earth leakage currents
Sometimes referred to as ground fault current or residual current, this is electricity that flows from the electrical installation to ground or other conductive materials in the home. Electrical systems are designed to pass current between the active conductors of the installation. When appliances like kettles, refrigerators, and washers become faulty, they can allow current to flow through their metal parts to your body and to the floor. This is a dangerous situation known as an earth leak. Certain types of circuit breakers known as residual current devices or ground fault current switches trip when they detect this current flowing into the ground to protect it from electric shock.
