Co.Design

Why Britain Has The Best Wall Sockets On Earth

The rest of the world has a lot to learn from the design of the U.K. wall plug.

Anyone who has traveled to the United Kingdom has probably marveled at the imperial bulk of the standard U.K. wall plug. With three chunky, rectangular pins, the design at first glance seems almost ridiculously inefficient, especially compared to the svelte footprints of the U.S. and European wall plugs, which manage to get juice to your electronics in under half the space.

But first impressions can be deceiving. In fact, as Tom Scott explains in a new video, the U.K. wall plug is a design classic that is substantially safer than any other plug design on Earth.

The main thing to know about the U.K. wall plug is that while it is bulkier than other designs, every ounce of that additional bulk makes the design safer. This is accomplished in four main ways:

Prong Design: Like standard U.S. grounded plugs, the U.K. wall plug has three prongs. But the design of these prongs makes it nearly impossible for you to shock yourself accidentally. Unlike in U.S. plugs, half of each prong is coated in insulation. Because of this, even if a plug is not fully inserted into a socket, touching the exposed part of the prongs can't give you a shock.

Socket Design: Any kid with a fork or a screwdriver can light his hair on fire in the United States by jamming it into a wall socket. Not so in England, where it would take at least two screwdrivers to manage the same calamitous trick. The U.K. plug is designed so that the grounding prong is slightly longer than the prongs responsible for transferring current. Like a tumbler in a lock, this grounding prong is responsible for "unlocking" the socket, giving access to the more dangerous live and neutral terminals.

Built-In Fuses: During World War II, a copper shortage resulted in the British government putting fuses into every plug, instead of wiring them directly. Although the built-in fuse adds bulk to the U.K. plug design, it's also safer: In case of an unexpected electrical surge, the fuse simply blows and the electricity shuts off, preventing fires, electrocutions, and other accidents. It also makes U.K. plugs easier to fix.

Circuit Design: Finally, there's the wiring inside the plug itself. Not only is it extremely intuitive, but it has been thoughtfully designed so that if the plug is tugged and the wiring frays, the live and neutral wires are the first to become disconnected, while the grounding wires—the ones responsible for preventing human electrocution when they come in contact with a circuit—are the last to fray.

It's a truly brilliant design. The only caveat is that, as with Lego, the rugged, bottom-heavy design of a U.K. plug makes it an almost scientifically perfect caltrop.

[H/T Metro]

Add New Comment

84 Comments

  • ELECTRO-DJ

    USELESS DESIGN - Earth pin NOT REQUIRED

    Not all electrical appliances require earth connection for safety. Many 3-pin UK plugs have a USELESS plastic earth PIN - just to open the wall shutters

    USELESS MATE ! Not Best !

  • I believe that in all of the plugs you are talking about are actually battery chargers. The Grounded pin is primary targeted at machines that could short out onto a touchable piece of metal . The ground pin in many larger appliances (such as washing machines and electrical ovens )

    Devices that come from abroad such as the US and Japan would require a redesign to work 100% with grounded pins

  • American plugs do seem like toys compared to the UK monsters, but they do work just fine. I have to wonder if the UK design is safety overkill? How many people die in the US due to plug related accidents?

  • Warren Chrismas

    The Earth wire is green AND yellow and therefore distinguishable from live (brown) and neutral (blue) even if you're colourblind. Is that a UK thing, or global?

  • Steve Jones

    It's a European standard. Up until the colours were harmonised, UK wires were green for earth, red for live and black for neutral, which is reasonably intuitive. Following European standardisation this became yellow/green for earth, brown for live and blue for neutral. Quite why brown (the colour of earth) was chosen for live, I've no idea as that seems the very definition of unintuitive.

  • Ang Yeow Lam

    0:46 the extension is not having a bad design, 2 headed plug can actually be plugged in with the help of 3 headed plug with such design

  • jcpkozio

    Hehe, nice explanation, but this design is made for customer to pay more as this plug is much more expensive and for manufacturer to spend less on electrical appliances, as plug is polarised itself so electrical appliances don't need to have one electronic part which basically "finds" hot and cold wire to pass them properly (straight or switched) to further internal circuit boards :), there is nothing about safety as all world standards give same safety, nothing about fire, as normal fuse board has 2 levels of safety and never let fire is not altered by brainless user.

  • Missed one thing - that the cable is at 90 degrees to the pins so that you can't just pull it out by the cable, weakening the connections on the inside, you have to grip it properly by the casing.

  • jcpkozio

    So if you accidentaly hook with leg cable on floor you brake both socket and plug, :)

  • edwardhendy

    The wall sockets and the plugs are insanely robust, though.

    My counter-point would be that the positive engagement afforded by the orientation of the cable and the shape/orientation of the prongs means that you don't accidentally pull the plug from the wall when you lightly tug on the cable like you do with a two-prong design. This happens constantly with an inferior two-prong design when you're vacuuming/hoovering, for example.

  • Chris

    Not sure whether you ever used a Schuko plugged vacuum cleaner but even though it is straight it will not easily pull out of the wall. But if you accidentally pull it with force, nothing is broken, just power is off. And it is very easy to design Schuko plugs with a 90 degree angle, in fact, many Schuko plugs are designed that way.

  • edwardhendy

    And yet we're on 240 mains voltage. There goes your perfect(ly stupid) metaphor!

    Dumbest comment yet.

  • merynda835

    They're not the most attractive though and inconveniently chunky for mobile appliances. I'm happy with the slimmer 3-prong plugs that we use in Australia (and China) along with socket switches for safety.

  • Frankie Sparkes

    You missed something. Switches are installed on all consumer sockets as of 1967 with the exception of Sockets designed for The Fridge, Cooker, Washing machine and, in some cases, dishwashers (they have external switches fitted on the walls), Block adaptors and Most 2-4 Way Extentions

  • Pranav Singanapalli

    This is silly. Columbusing the electric plug. I see all the same features in other plugs as well despite being half the size. I regularly use electrical goods purchased in UK, US, Germany, China, Japan and India. The only unique feature is the easily replaceable fuse, which if I am honest is only a good use of the plug's humongous size. Can someone care to explain why that was needed? I can't remember the last time I had to replace a fuse , the MCBs in my home seem to function quite well.

  • Frankie Sparkes

    Here's your answer to the question "Why was a fuse required?": It's because the UK operates on a Ring Mains, unlike the rest of the world, which is in most circumstances cheaper and considerably safer. Alongside that, MCBs aren't meant to operate in normal circumstances. MCBs are a current protection device that trips when input and output current is different, usually between 30-63mA different. It is not designed to operate in times of a short circuit, that's what the fuse is for

  • Demon Lee

    Actually, a ring main, because it supplies current from both directions, can have numerous undetected faults and it much more difficult to test - ask any competent electrician.

    It is NOT cheaper as being a RING MAIN, each circuit supplied often has to travel a greater distance to return to the Consumer Unit....!

  • I can't remember the last time I was in a head on crash at 60 mph, but I'm thankful that I'm driving a car with a high safety rating. If only all cars were that safe...