PSA: The Steam Controller’s magnetic charger can be a fire hazard

Keep the charging puck’s exposed pins far away from anything metal.

See full article...

 

[Randomizer]

The watch was a Pixel Watch 3. These use induction chargers. Could the Pixel charger induce enough current in a metallic strap to cause damage if the watch was still charging when it contacted the pogo pins? I think that it's highly unlikely.

I must have seen a dozen YouTube videos of Americans heaping praise on the Type G plugs we have in the UK. They have at least five safety features, except one to stop you standing on them in bare feet, which hurts. Imagine standing on an errant Lego brick then multiply that by three.

• Earth pin is longer so is always the first connection.
• L and N pins are covered in plastic for most of their length so by the time they are connected there is no exposed metal.
• Plugs have a fuse rated for the appliance; there’s no need for a table lamp to draw more than 3A, so that’s what the fuse is.
• If you somehow manage to pull hard enough to rip the cord out of the plug the wires inside are cut to different lengths, such that the live wire is the first to be disconnected.
• The L and N connections in the socket are behind plastic doors that are opened by the earth pin, so it’s pretty much impossible for a child to stick anything into a socket that doesn’t belong there.

That plug is one of the most over-engineered plugs in existence. The UK is unique in that it allowed "ring circuits" for AC power, when every other country used branch wiring, so the safety fusing had to be integrated into every plug as well as the fusebox, and this made the UK plugs so huge to accommodation room for a fuse.

By the by, I’ve often wondered why American sockets aren’t installed upside down. Having the earth pin at the top would stop the rare instances of something conductive falling onto a half-inserted plug and shorting live and neutral.

That's common in commercial wiring now, to the extent that outlets sold/designed for commercial use have the markings "upside-down" relative to outlets sold for residential use.

US plug designs also make it almost impossible to have partially "sleeved" conductors (where only the ends are conductive) or to have recessed plugs. Recessed plugs are used for some AV installations, but that makes them incompatible with many power cords that have the power leads coming out of the side because recessed outlets are not a standard in the US.

It's a very poorly designed plug from a safety perspective. The standard was locked in very early in history and it's almost impossible to update at this point without obsoleting enormous numbers of appliances.

 

[Randomizer]

Another EE here, based on the reddit link above it looks like it might have been caused by a ground loop. The power itself maybe not have been directly generated by the controller puck or the pixel charger, but a circuit forming between the two. If that was the case, it's possible that the voltage and power going through the watch band was much higher than either charger could produce. Like others have mentioned US home power layout can have issues that places a voltage potential on what should be a neutral or grounded line. The cavate here is that good chargers should isolate everything on the low voltage side, but like most things that is a should and not a 100% do. Isolation of grounds is not always a given simply due to the nature of what a ground is expected to do.

What ground loop? The Pixel charger uses inductive charging.

EDIT - I stand corrected. Comments below show that the Pixel 3 charger uses actual pogo pins in their charger as well. That definitely opens up the possibility for a short circuit.

 

[Randomizer]

I would love to see electrical code updated to include smarter breakers, though of course then people will complain about having to go to the panel to reset vs a gfci outlet chain

It's not just that - it's that AFCI/GFCI combo breakers breakers are very expensive ($70ea, as opposed to basic 20A thermal breakers going for $7) and also have issues with nuisance tripping, especially when using anything with brushed motors. Older vacuum cleaners are especially are terrible with these.
GFCI breakers without Arc-Fault detection do absolutely nothing for arcing and may not trip if you briefly short neutral and hot. They trip when there is a current difference between neutral and hot, which is why they are strongly recommend wherever there are outlets without ground, and they have to be labeled "Not Grounded".

 

[Randomizer]

You can solve that by not putting electrical outlets in bathrooms. The only ones we have are for shavers and electric toothbrushes. They’re limited to 110V, have an internal fuse, a different plug and they’re galvanically isolated so there’s no risk of electric shock unless you actually set out to electrocute yourself.
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The US is all on 120V, and outlets in bathrooms have been required to have GFCI outlets for at least 30 years now, AND every hair dryer in the US must have a GFI circuit in the plug as well (which I don't like - they are big, bulky things). It's practically impossible to electrocute yourself with a hair dryer in the US.

Breakers tripping due to overloads - if the house wiring is so shoddy (or so old) that a single hair dryer trips "half the house", that's 100% an issue with the house. This is NOT AT ALL typical in the US.

 

[Randomizer]

I still haven't figured out how a lot of hair dryers can legally be sold. I see some that are labeled at 1875 watts, which is more than 15 amps at 120V. How can such a device be sold with a 150-amp plug instead of the 20-amp plug?
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Although actual voltage is nominally ~120V, outlets (and the NEMA code) are rated for 125V, I think to account for possible regional or temporary voltage variations. 125V x 15A = 1875W.

 

[Randomizer]

Is there a good reason you couldn't use inductive charging like on most phones and many watches? I'm not an EE and I know it'd be less efficient, but with Qi2 charging at up to 25W it doesn't seem like it would be a problem with time to charge. Is it more a matter of the space needed? Even the Apple Watch can charge at up to 20W from what I read.

I'm not trying to troll here; I am genuinely curious as it seems the inductive charging would avoid the shorting issue altogether.

Kevin

The inductive coil adds a little bit of thickness and weight, and they tend to get very warm when charging. There are advantages and disadvantages to both approaches.
Is there a good reason no one takes the approach to charge via a single pin and then use a resonance frequency to couple the device and charger? It would be similar to wireless charging but without large coils and wasting energy on pumping EM fields, and you only need to align on a single pin, so orientation wouldn't matter.