PHYSICS

Sparks (don’t) Fly ⚡

Imagine your house as a bustling city with electricity as the lifeblood flowing through its streets. To keep everything running smoothly and prevent any potential disasters, we need some sort of British Transport Police - these are our miniature circuit breakers (MCBs). Have a look in your house, in that cupboard where all the stuff is and you will probably find yours.

MCBs are essentially tiny switches that protect electrical circuits from overloading or short circuiting. Think of them as safety valves, preventing electrical fires. If the current flowing through a circuit becomes too high, the MCB will automatically trip, cutting off the power. Inside an MCB, there's a bimetallic strip, which is made of two different metals joined together. When the strip heats up, it bends due to the different expansion rates of the two metals. If the current flowing through the circuit becomes too high, the bimetallic strip heats up enough to bend and trigger a mechanism that breaks the circuit.

There are three main reasons we tend to use MCBs.

Safety: MCBs prevent electrical fires and shocks by cutting off the power before a dangerous situation can occur.

Convenience: If an MCB trips, it's usually a sign of a minor problem that can be easily fixed. This is much more convenient than having to call an electrician every time there's an electrical issue. Imagine the electrician’s bill for that!

Efficiency: MCBs help to ensure that electrical systems are operating efficiently by preventing excessive current draw.

💡 Things to consider

• MCB ratings: MCBs come in different ratings, which indicate the maximum current they can safely handle. It's important to choose the right rating for your specific application. The rating is usually specified in amperes (A) and is typically matched to the electrical load of the circuit it’s protecting. If you choose an MCB with too high a rating for your circuit, the breaker might not trip when there’s an overload or short circuit, which could lead to overheating and, in the worst-case scenario, an electrical fire. On the other hand, choosing an MCB with too low a rating can lead to frequent tripping, even under normal conditions, causing unnecessary disruptions in your electrical supply.

• RCCBs: MCBs can only protect the appliance from overheating and catching fire. To protect the user (you) of the appliance, we would need to use a Residual Current Circuit Breaker (RCCB) to minimise the risk of electrocution. An RCCB detects discrepancies between the live and neutral wires (such as when current is leaking somewhere outside the circuit, possibly through a human body) and will trip to prevent electrocution. Without an RCCB, a person could potentially receive a dangerous shock even if the MCB is functioning perfectly.

• Electrical safety: While MCBs are a crucial safety measure, it's still important to follow basic electrical safety practices, such as avoiding overloading circuits and using electrical appliances properly. No amount of MCBs or RCCBs will protect you from a toaster in the bathtub!

  

  Indeed.

🔎 Find out more

• Listen to the Megger Watt’s up podcast episode about circuit breakers

• Read REALPARS’ blog post where they explain, in detail, how circuit breakers work

• Watch John Ward’s video to see the inside of a circuit breaker

🍒 The cherry on top

• 😱 The Science of Fear: Scripted horror reigns on TV. From “American Horror Story” to “The Walking Dead,” vampires, zombies, and ghosts are now more prevalent on American screens. Why are we so drawn to these thrill-seeking horror shows? This is a great read if you’re into Psychology or Biology

• 🌍 Social Media and Global Politics: How has the rise of social media platforms affected political discourse, elections, and international relations? This article explores the complex relationship between social media and politics in the 21st century. Relevant for students interested in Politics, Sociology, or English.

• 💸 Behavioral Economics: Do humans defy logic and reason when they make financial decisions? Explore the ways psychology informs economic decision-making with this (very short!) four-part Behavioral Economics Digital Lesson Series. Great if you’re into Economics or Psychology.

👀 Keep your eyes peeled for…

• 3rd February

  • Trinity Hall Cambridge History Webinar

• 4th February

  • UEA Biology Webinar

  • Trinity Hall Cambridge Asian and Middle Eastern Studies Webinar

  • Trinity Hall Cambridge Linguistics Webinar

• 5th February

  • York St John University Subject Showcase Day (range of subjects)

• 8th February

  • Oxford Physics Taster Morning

  • Royal Holloway University of London Girls do Engineering Day

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