29 Jul The Evolution of Safety Switches – From ELCBs to RCDs
A safety switch is essentially a device that very quickly switches-off the electricity in case any electrical fault is detected. In effect, it reduces the risk of injury & death caused by contact with electricity. Current day safety switches are very different from the ones used even up until a decade ago. Today, it’s mandatory to have these installed in buildings where any kind of electrical addition or upgrade has taken place.
Apart from this, safety switches are also needed for power outlets that that supply electricity to mobile homes like caravans etc. It’s not mandatory to have these safety switches in older homes; however, the recommendation is that you should consider getting them installed. It is one of the most effective ways to protect your family & yourself from electric shock.
ELCBs or Earth-leakage circuit breakers are safety devices used to prevent shock in electrical fixtures which have high Earth impedance. The current installations use the circuit breakers that directly detect leakage in current. Here are some features of an ELCB:
- It detects the erratic voltages on the electrical equipment enclosures, and interrupts the circuit if it detects any dangerous voltage
- If a sufficient amount of voltage appears across the sense coil of the ELCB, it switches off the power, and then remains off until its manually reset
- This type of ELCB doesn’t sense the fault currents from a live to other Earthed bodies
- This category of devices is specifically used to protect circuits, instruments and operators in case there is Earth leakage
More Information About RCDs/RCCBs
RCDs or RCCBs are essentially modern electrical wiring devices which quickly disconnect a circuit if they detect that there is an imbalance in the current between the energized conductor/s & the return conductor. They are designed to immediately switch-off the electricity supply when the electricity leaking to earth is detected to be at harmful levels. These devices offer very high levels of protection from electric shock.
A peek into safety switch history
Voltage Earth-leakage circuit breakers were first introduced around 60 years ago, while the current ELCBs were launched only around 40 years ago. For a very long time, voltage-operated ELCBs & differential current-operated ELCBs were both called ELCBs; this was because it was a far easier term to remember. However, as expected, this common name caused a significant amount of confusion within the electrical industry.
If someone accidently used the wrong one in a particular application, the installations may not get the kind of protection it needed. It was to eliminate this confusion that the International Electrotechnical Commission decided that the differential current-operated ELCBs will be termed as RCD (residual current devices). Any current that’s over & above the load current is referred to as the residual current.
Why ELCBs have given way to RCDs
ELCBs have a number of disadvantages such as:
- If there is a wire break in the Earth to ground or fault to load section, it can cause the ELCB to fail – this can cause the user to get a very severe electric shock if there is an Earth fault
- An additional third wire is required from the load to the load to the Earth-leakage circuit breaker
- It isn’t possible to ground separate devices individually
Today the RCD is preferred means of providing effective shock protection. The term is also most widely used across the globe.
For more information about RCDs and the best electrical solutions, call Allround Electrical at 1300 169 263. You can also write to us at this email address. You may also reach us through this online contact form.
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