Learn about 4 top ways to cut power in potentially dangerous situations
Being able to break a dangerous circuit quickly is a crucial safety feature of mains wiring in the home. However, the fault conditions that can damage appliances or cause an electrical fire are often different to those that can potentially kill a person. Here are the big 4 safety solutions.
What is an RCD?
An RCD (residual current device) is designed to prevent harm to people. It compares the current flowing through the active and neutral wires; if a person touches a live wire, or if there is a fault that could cause electrocution, this causes an imbalance between the active and neutral. An RCD breaks the circuit within milliseconds, fast enough to prevent cardiac arrest. Always plug in a standalone or inline RCD when using power points that might not be running through the RCDs in a home's electrical switchboard.
Circuit breakers
Performing a similar function to wire fuses, circuit breakers are designed to prevent electrical fires and damage to wiring. They disconnect the power supply in response to an excessive level of current flowing through the wiring, which could melt components inside appliances and start fires. They are not intended to cut the power quickly enough to save a person from harm.
Overload protection
Most powerboards feature a resettable circuit breaker that shuts off the supply if the appliances connected to it are drawing a dangerously high level of current. This is known as overload protection, and it's important because excessive current through a powerboard can cause it to overheat and start a fire.
What about fuses?
Wire fuses are designed to overheat and melt when excess current flows through them, breaking the circuit. They are no longer commonly used in domestic applications, but still popular for automotive use. The shock from a faulty 12V accessory is unlikely to kill you, but if the wiring that supplies your car stereo overheats and the insulation melts, you're going to be faced with a fire risk and a very expensive repair bill.