There is a reason for USB-C extensions not to be part of the standard. They can be bothersome in the best case and dangerous in the worst.
Anybody care to sum this up for people who can’t watch videos?
So a standard cable needs to be chipped to show its rating to the device, its not that the device can pull what it wants or can get, but the cable itself tells it what it can supply. Extension cables can’t do that, because it doesn’t know what it’s plugged into, and that would be if they even bothered to put a chip in. They instead piggy back off the chip for the main cable. The problem comes when you you have a 240 watt cable hooked up to a cheap 120 watt cable, with the device being told it can push 240, and starts to super heat the extension cable
Brilliant thanks
5 sentences that inexplicably need a 9 minute video to say
Fuck YouTube
This sounds solvable, doesn’t it? Have the extension cable have a chip saying it can do X at maximum, then compare with whatever is to be extended and communicate the minimum of both upstream. Might not become a sleek cable-like design, but would extend the 240W cable with the extender safely staying at 120W
That’s an active extension cable, which is essentially a single port USB hub.
Heh heh heh. Wait till you dive into the world of “That $15 cable costs 12c to make.”
Well, the source checks the cable using the CC line which doesn’t go through the cable (VCONN). So source only knows the cable directly plugged in. To make the extension cable visible, the sink would be required to check the cable plugged in using VCONN and then the tell max ampere to the source over the other CC that goes through the cable.
2 Problems:
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Sink devices normally don’t read or can’t read VCONN as far as I know
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No way of detecting if a third cable (extension in the middle) is present and what specs it has
Correct, except for your example. Firstly, 120 watt USB c cables don’t exist, only 60w, 100w, 140w and 240w. And only plugging in a 100w or higher cable into a 60w extension would be dangerous, since it would allow drawing 5 amps on a cable over an extension only designed for 3 amps. However, as soon as your extension is rated for 100w it is completely safe to use with any USB c cable, even those rated for 240w, as those only operate at a higher voltage but still only allow 5 amps max.
I have also never seen an USB C extension cable rated for less than 100w, so this is kind of a moot point. If 60w usb c extensions exist somewhere, they would indeed be dangerous, but I have never come across one
Interesting, I’d never trust any USB cable to push anywhere near 100 watts anyway haha good god, the most I ever do is maybe 20w at 5v.
I’ll keep that in mind when buying cables in the future though this is very useful info!
As a point of reference, Lenovo Thinkpad’s have something of a cult following for their reliability and versatility.
My T490s has a USB-C power supply which provides 45w (20v at 2.25a).
The thing is, when docked it’s not only pulling power through that cable, but also network, USB devices, and providing video for 2x monitors in 1920x1080. It’s kind of astonishing to me how much can be crammed in to one little connector. That said, it’s frustrating trying to find a usb cable that works reliably, because as you’d imagine not all USB-C cables support the same specs.
If you buy a Steam Deck, or the Lenovo laptop I have for work, the only charging options you have are USB C. Their standard chargers put out at least 60 45 W, and they aren’t particularly special. In fact, I’m pretty sure 20 W at 5 V won’t be enough to supply these while in use, so you will either be using battery with long charge times in between, using them with battery-assisted power for longer use times until you hit those long charge times, or using the 60 45 W or more at whatever voltage the chargers provide.
My laptop can do 240W over USB-C, I’m just waiting for a charger that can do it with a modular cable
Safety regulations are written in blood. Electrical fires were indeed a problem. It’s why there are rules on how many outlets need to be in a room, how spaced out they need to be (to curtail extension cord usage even when the builders are trying to be cheap and stingy with outlets). It’s the reason why we have breakers and GCFIs and RCBs and AFCIs. It’s the reason why we have electrical certification bodies like UL which won’t certify your cable or appliance if the cords are too thin.
There’s a lot of smart stuff we do behind the scenes to make dumb cords safe because even smart people make dumb mistakes.
“Dumb” power cords have thicker gauge wire than USB-C cables and much larger contacts.
Going to take a wild guess and say the same reason you shouldn’t chain extension cords. USB can carry over 200w these days.
the same reason you shouldn’t chain extension cords.
what if I don’t know that either
Chaining regular extension cords isn’t a problem by itself, connecting too many things in parallel and exceeding the rated max is a problem (and chaining extension cords “just” increase the risk that ordinary people will decide to connect more than they should, especially because the lowest rated cable in the chain sets the total limit)
The issue of chaining extension cords is that you can physically plug a 10 amp extension cord into a 30 amp cord. If you don’t know what amps the device will pull, the 10 amp cord can overheat.
It’s an almost identical problem to USB c.
Yeah, I think in this case there’s a lot more tiny conductors sharing what can add up to pretty high current loads on PD connections. Adding extra connectors adding resistance to low (5-20v) voltage high current connections is adding an extra failure point and increasing resistance on the whole cable run.
Not inherently unsafe, but just not a good idea to promote because you know someone will try to run a 200w charging cable for 30m with like 5 connected cables.
This is what AI says about this video:
The video is about the dangers of using USB-C extension cords. The narrator explains that USB-C extension cords are not officially certified by the USB Implementers Forum, which means that they are not guaranteed to be safe or reliable. He also explains that USB-C extension cords can be dangerous because they can overload the power supply of the device that they are connected to. This can cause the device to overheat and even catch fire. The narrator recommends that people avoid using USB-C extension cords altogether. Here are some of the specific dangers of using USB-C extension cords:
- They can overload the power supply of the device that they are connected to.
- They can cause the device to overheat and even catch fire.
- They can degrade the performance of the device.
- They can be unreliable.
The narrator also explains that some USB-C extension cords have a label that says “USB 2.0 low speed devices can only work with one side of the ultra high rate extension cables interface.” This means that the USB 2.0 connection is only available on one side of the cable. This can be a problem if you need to connect a USB 2.0 device to the cable.
The narrator recommends that people avoid using USB-C extension cords altogether. If you must use one, he recommends that you use a high-quality cable from a reputable manufacturer. You should also make sure that the cable is rated for the power requirements of the device that you are connecting to it. Overall, this video is a helpful resource for anyone who is considering using a USB-C extension cord. It provides important information about the dangers of using these cables and how to avoid them.
As always AI doesn’t quite get it. One of the main points is that it could catch on fire and burn down your house. Plus you’ll run into other problems as well. You’re not supposed to buy extensions for USB. Buy a longer cable instead.
I need the super duper reliable video summary LLM I was promised. Or else!
I even bought my pitchfork for it, see? ----₤ What? It was on sale.
It’s not that Lemmy hates videos and AI. Lemmy (understandably) hates YouTube* videos and AI.
We the Fediverse have our own video platforms, such as Peertube, and more recently, loops.video. Linking to YouTube defies a golden purpose that motivated us as the fediverse: privacy, no tracking, no ads, no enshittification.
The risk isn’t usually the device you connect a bad cable to (they have internal limiters), it’s the cable itself. You can easily overload a cable if the extension cord can’t signal the lower limit if it’s own rating and the other cable’s rating.
The USB 2 part is also misleading.
