I’ve been clearing stuff out at home, and a big chunk of that clear out has been cables. I was throwing out a ton of US extension cables (I worked in the US for a while), and two things struck me:
1: None had fuses in. I even hacked one of them apart to check.
2. Some of them weren’t earthed.
This got me thinking about safety & stuff. The plug receptacles will be protected by the circuit breaker at the fuse box – but that will only protect the cable in the wall to that central distribution cabinet won’t it? Assuming it’s say a 20Amp breaker (I don’t know what they actually are), that means you could have 20Amps (or 2200watts) being pushed down an extension cable rated for less than half of that. Seems a recipe for a bonfire doesn’t it?!
Throw in some daisy-chained extension cables etc. and that sounds disastrous. What am I misunderstanding here? Anyway, it got me further thinking about how we do things in the UK.
We of course have similar circuit breakers in the UK, although I think they’re typically rated at 32amps – which is 7680 watts. Our extension cables and plugs however are fuse protected – typically with a 13amp fuse. A 13amp fuse will allow up to circa 3120 watts at 240v before the fuse blows.
Yet everything is fitted it would seem with 13 amp fuses, regardless of power-draw. While it seems a lot safer than the US system it does seem like a blank assumption that 13 amps is the right protection point.
My main tech stack for example consists of 5 extension cables configured in a star formation. I.e., one ‘master’, and four connected to that master. Sounds excessive until you look at the load:
It averages about 150w during general day to day usage, which is about 0.62amps. Tiny. Even at full power on it peaks at about 500watts for a couple of minutes – again only 2.08Amps. So why would it be protected by a 13Amp fuse? It isn’t any more, it has a 3amp fuse in it and it powers up just fine. If it blows, I’ll put a 5amp fuse in I think. It’s all UPS protected anyway.
I had a brief scan around other things – Microwave, 13amps (reasonable), Kettle 13amps (reasonable), TV 13amps….Lol wut. I’ve never seen my TV pull more than 150watts so why on earth is it protected with a 13amp fuse? Just because, I guess. Same on the Playstation 5.
Anyway, I am probably obsessing over something I found vaguely interesting. Firstly, my sudden perception of how unsafe the US model of extension cables & power control seems to be, and secondly with our obsession with 13amp fuses over here in the UK!
I will say though that I think the UK plug is an absolute master of design. It would also seem I’m not the only one to think so!
I’d love to hear perhaps a better educated opinion on the matter.
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