Without knowing it, you’re probably very familiar with circuit protection already. Circuit protection – at its most basic – is the idea of introducing a weak link into an electrical circuit to protect both users and equipment. The point behind this weak link is to safely trigger the shutdown of electricity in moments where there might be a power surge or short circuit – thereby avoiding damage to electrical equipment and, potentially, users.
Faults can happen in electrical circuitry for many reasons; however, the most common are overheating, short circuits, or a surge of excessive current. In these events, the weak link circuit protection will be triggered to stop the flow of electricity.
Common types of circuit protection
There are many different types of household circuit protection available from sites like powerpointelectrics.co.uk; however, the most common protection devices include:
Fuses: Fuses contain a thin wire which melts when excessive electricity is introduced. The wire is destroyed under excessive current, thereby breaking the circuit to protect the device then. There are various fuses, including rewireable fuses, cartridge fuses, and High Breaking Capacity (HBC) fuses.
Miniature Circuit Breakers (MCBs): Unlike fuses, Miniature Circuit Breakers are designed to be reusable but perform a similar role – namely to protect equipment from overcurrent. These small electromechanical devices act as a switch, effectively tripping a latch to isolate the supply of electricity. MCBs tend to be much more expensive than fuses – however, their reusability stands in their considerable favour.
Residual Current Devices (RCDs): Residual Current Devices are used to protect against an earth fault and will disconnect electricity in the event of an error (for example, if a live conductor has been cut through by accident). RCDs are highly effective in preventing electrical shocks or fires.
Residual Current Breakers with overcurrent (RCBOs): Residual Current Breakers with overcurrent protect against earth faults only making them unsuitable for use as the sole protection against current loads.
Why is circuit protection important?
From a health and safety perspective, circuit protection is essential to maintain both the safety of users and the integrity of the equipment. Well-designed circuit protection will localise and isolate faults while also preventing avoidable power loss.
Almost all modern homes have an electrical breaker monitoring the supply of electricity for the entire home – split into individual circuits. You’ll commonly have seen these circuit boxes contained in a small cupboard, typically near the front door in homes and apartments.
Breakers all work similarly and are intended to interrupt the supply of electricity when there’s a short circuit or overload. Unlike fuses, common household circuit breakers can be reset (rather than replaced).
Tips for using circuit breakers
If you find a cut in power, it’s important to try and isolate what’s causing the problem – and your circuit breaker board will likely have the answers. It’s quite likely you’ll have connected too many devices in a particular room, so try turning off all the individual breakers, then the main breaker last.
Reset the whole process by switching on each breaker, one at a time, to try and isolate where the problem might lie while avoiding the same potential power surge. When resetting the main breaker, it’s often a good idea to turn your head to the side and wear safety glasses to avoid potential flashes or sparks.