Rubber Box Industry Insights: Systems That Keep You Safe
When discussing our power distros with customers, we sometimes get questions about specific engineering terms. And although we try to avoid unnecessary jargon when talk about our power distribution systems, some of our customers like to get a little bit of a head start on some industry language where they can. With that in mind, our blog this week follows on from our previous one. Today we’re talking in straightforward, clear terms about some of the main devices that keep you safe, and the mechanisms behind the way they do it. It’s not required reading, but you might find it helpful!
This week we’re answering the questions:
- What is an MCB in electrical engineering?
- How does an MCB work?
- What does RCD stand for?
- How does a residual current device work?
Mains or Miniature Circuit Breaker
MCBs are one of the bread-and-butter safety devices, commonly installed in residential buildings. Essentially, they act as resettable fuses, so in order to explain how MCBs work, it’s first necessary to explain the workings behind their disposable counterparts. Fuses are basically thin pieces of wire designed to carry a limited electrical current – when the current passing through them is too high, they heat up so much that they burn or melt, destroying themselves and breaking the current in the process.
So how does an MCB work, exactly? Well, an MCB functions on a similar sort of principle; it’s basically a switch that turns off the circuit in the event of an abnormally high current passing through it. The actual process is obviously very complex, but in its barest form: high currents cause certain specially-designed components to move out of position inside the MCB, breaking the circuit and therefore the current. However, unlike fuses – which need to be replaced – these components can be reset just by flicking the switch again, making MCBs far more convenient and economical than disposable fuses, as well as making them safer to handle.
Residual Current Device
RCD stands for Residual Current Device; it’s another commonly used device to protect both appliances and lives. It’s common knowledge that electricity typically behaves in two ways – it always heads towards the ground, and it always takes the path of least resistance. This can be bad news, because it means that in the event you accidentally cut a wire – with a power tool, for example – you become part of the circuit, with the current coursing through you instead. In the case of mains electricity, that can be deadly more often than not. What the Residual Current Device does it shut off the current before it reaches you, thereby saving your life.
How the RCD works is by constantly measuring the output of both the live and neutral wires that make up the circuit. In order for it to continue functioning correctly, they both need to be consistent. However, if their output isn’t equal, it signifies a ‘leakage to earth’ – that phrase refers to the electricity that’s likely to try and use your body as a vehicle to get there. In the event of a leakage to earth, the stray electricity flows into the RCD instead, which is designed to react by cutting off the power. It typically does this in around 30 milliseconds – far faster than it would take you to finish cutting the wire, therefore saving you from an unpleasant and likely quite fatal experience.
Safety Is Always Our Top Priority
These aren’t the only two safety devices on the market, but they are two main types. An RCBO, for example (a Residual Current Breaker with Overcurrent) basically combines the functions of the two. All of our Rubber Box products come with some form of overload protection and safety devices, even though it might not specifically be MCBs and RCDs, depending on your needs and the design. In every case, your safety is the highest priority for us, so you can count on our qualified electrical experts to provide honest, professional advice.
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