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.
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
Haven’t you heard about Raid Shadow Legends?
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1m USB-C CABLE HEATER!! 0.99c
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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.
Shouldn’t it be possible to only do the negotiation part and otherwise bridge everything? Not having to do anything high-bandwidth actively should keep the silicon costs down.
Yes, and such cables already exist, like this splitter cable:
https://www.amazon.de/dp/B0CRZ6JJ6D (not an affiliate link)
It’s not an extension cable, but it does exactly what you are suggesting. It gets the available PD profiles from the charger and then intelligently negotiates a profile that will work best to split the power to the 2 devices connected to it. The charger thinks it’s just connected to 1 device, and the connected devices think they are directly connected to a charger.
Doing the same for with a USB C extension would be trivial, but it’s probably hard to market such a cable when passive USB c extension cables are available at a fraction of the cost, even if those aren’t compliant to the USB standard
I wish there was a clearer explanation or nomenclature for this. With things like cables and converters everything always seems to have a black box layer.
I don’t understand why there are so many PD profiles either. Maybe Cat-1 USB-C, Cat-2 USB-C, etc? Maybe just having a smaller set of voltage-defined profiles that have a safe maximum current rating? Maybe that’s already how it is? I don’t know
There are technical reasons for why so many PD profiles exist.
In fact they were not enough, which is why the USB Standard was extended with the “PPS” extension recently, which let’s the attached device freely choose a voltage between 3V and 21V in steps of 20mv, and more importantly it let’s the device freely change this voltage without interrupting the charge process. This change makes it possible for devices to bypass their own but in charging electronics and just directly forward the voltage coming from the charger to the device, improving efficiency and significantly decreasing how much the device hears up during charging
Sadly PPS is not found on many devices or chargers yet, and makes the already complicated USB C charging situation even more complicated for consumers
I am highly sceptical of anything that would connect USB voltage, no matter how finely negotiated, directly to the battery terminals. Finely tunable voltage over USB is useful for keeping the buck/boost converter on the device side small, though, or just efficient because it doesn’t have to do as much work. If you can charge over standard PD extending to charging over PPS should only be a software change as your hardware is already more than capable.
Heh heh heh. Wait till you dive into the world of “That $15 cable costs 12c to make.”
Getting $30 cables for $3 with my employee discount was almost the only good thing about working for Best Buy in the early 2000s.
I’m right now in China and those cables cost $0.50 shipped to your address, so not surprised
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:
Sink devices normally don’t read or can’t read VCONN as far as I know
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
Well I’m glad I know that now.
Pretty much this, thanks for the summary
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.
Is the dock USB-C or Thunderbolt?
It’s USB-C.
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
6045 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 the6045 W or more at whatever voltage the chargers provide.The Steam Deck charger is 45W.
While this is handy to know, it doesn’t negate my point.
IIRC the one that came with my OLED model is 65WIt appears I did not remember correctly
I’m looking at the one for my OLED deck right now and it’s labelled as 45W (20V 2.25A).
The ones I’ve seen that go over 45W specifically for the Steam Deck are mini docks with HDMI out and more
My laptop can do 240W over USB-C, I’m just waiting for a charger that can do it with a modular cable
It has a 240w charger but have you checked to see that it’s using all 240w?
Most laptops use (up to) 120w.
It can use almost all of it using the GPU
What’s the make and model of the laptop?
Framework 16
Site says the power adapter is 180w
https://frame.work/blog/framework-laptop-16-deep-dive---180w-power-adapter
How did we possibly survive with entirely dumb power chords?
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.
This is not about contacts but cableburning tho.
Hence the thicker gauge wire.
Going to take a wild guess and say the same reason you shouldn’t chain extension cords. USB can carry over 200w these days.
what if I don’t know that either
It all depends on current draw vs wire size over distance.
No, that’s not the reason at all. The actual reason is a phenomenon called “loop impedance”, which increases exponentially with each additional plug connection you chain together, regardless of the wire guage and distance of the extension
Too high loop impedance can cause your RCD to no longer trigger if you accidentally touch an exposed live connection, which is a major electrocution risk
Are you referring to AS/NZS 3000? I’ve never come across that here in the states, that’s some interesting reading and makes perfect sense.
On the practical side without engineering calculations, daisychaining extension cords will simply exacerbate voltage drop, which coupled with increased line resistance, will just cause increased current draw and increased thermal dissipation on the cord (those cords everyone’s dad has where the outer jacket is shrunk to hell against the internal wires), and poor reactance of (especially motor driven) equipment. This can be alleviated by using thicker cords (eg #10), but it still has limitations over excessive distance. A small battery charger will probably continue to work, whereas a table saw will have problems.
On the safety side, even sticking your finger on the load terminal of a 20a breaker will not trip it, even barefoot, as the human body doesn’t draw enough current, it just zaps the hell out of you. OCPDs are typically designed for system and equipment protection. GFCIs are more effective at protecting a person, but only if the current deviates to a different ground path. As far as I can tell from preliminary reading, the purpose of calculating loop impedance is determining the effectiveness of the grounding (earthing) conductor in relation to distance from the actual transformer. In a real world scenario, this is more going to be say if a cord were to be cut or equipment faults to ground, and whether the impedance exceeds the physical limitations of the wire to trip the breaker (or fuse).
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.
Why in the everloving would your electrical code allow sales of extension cords that can’t withstand the whole of the plug/socket rating. If it’s an adapter from a higher amperage plug to lower amperage socket you need a fuse.
The short answer is rating changed. We got more and more devices that required higher amperage ratings. So we went from 110 (which was what most homes were rated for in the 50’s) to 120. But if you happened to have an old extension cord lying around in your basement from before the change etc you absolutely could overload it.
The real problem though is that some devices you might use an extension cord for (lets say a welder because I know from experience those require more power than a standard 20’ extension cord puts out), require a certain gauge of wire to carry that power. If that wire is too small or the power source is insufficient, it’s likely no electricity will flow (without flaws in the circuit).
There are various kinds of extension cords made for various uses. Longer = more money, fused = more money, larger wire = more money. More insulation/weather proof plugs = more money.
You probably don’t need a big beefy extension cord for the lamp in the hallway. But you might need it for your weedwacker.
But if, say you hooked up an outlet dedicated for something like a washer/dryer. And you used the correct extension cord to connect to that outlet. Now let’s say you attach an older extension cord or power strip to that extension cord. One that doesn’t have an internal breaker to trip (there’s definitely a fair number that didn’t, back in the day). It would be an astronomically bad idea to attach your welder (or any high draw device) to that circuit. You absolutely can and will let the smoke out of your wires and where there is smoke there is fire.
110/120 is the voltage. That’s irrelevant to the amperage, which is somewhat standardized as 15a on normal outlets and 20a on kitchen or garage outlets.
Extension cords do not have fuses/circuit breakers. That’s found in some power strips but it’s neither required nor necessary with proper use.
And I can literally only reach my car with a welder if I use an extension cord…
The risk of daisy-chaining power strips is it become very easy to overload it, so yes, a circuit breaker would be nice as fire protection. 17 phone chargers would be fine but heating appliances will overload it fast. With no internal breaker, it’s easy to cause a fire with really cheap strips but, if life was ideal, they’d all be made to handle 20a loads like the receptacle in the wall.
The risk of daisy-chaining extension cords is the extra resistance incurred at each connection. There’s a varying amount form the imperfect contacts and a varying amount from pulling the cords apart over the time of device use. If you keep burning plugs with your yard care equipment, it’s probably not normal. It’s usually from partially unplugged cords trying to carry 10-20a across half the planned plug contact. You can readily buy 10-16 awg cords in 110v markets. It’s up to you to determine the appropriate gauge. In an ideal world, they’d all be 10awg. But we don’t have that, we have a world where you can actively choose to save money and increase risk.
Yes, that is a risk. Don’t forget about voltage drop, though! A short extension is generally quite a thin conductor, and the thinner the cable, the more resistance you get in the cable itself.
Some extension cords absolutely do have circuit breakers, I know this because we use them at work for some of our heavy duty equipment. I also know for a fact that fused link extension cords were their predecessor and you can buy both on Amazon still so I know they exist.
Further I was not saying don’t use an extension cord with a welder. I was saying the correct gauged wire for that extension cord may be necessary to carry the load.
The point of bringing up 110 vs 120 volts was to point out that more voltage = more push. More push through a smaller circuit than is recommended means more heat.
Amperage is the draw, and it’s important because most devices are rated by draw rather than voltage, so what I said does make sense in that context. I wasn’t trying to say they were the same thing. The reason they’re rated in amperage is because the amperage is what kills you, and because thats what the safety devices are rated in. That’s how much of a draw they can withdtande before they break the circuit.
I was also pretty exhausted when I responded so my explanation barely makes sense even to me, but I do see where I was going with that. Have you ever seen one of those old brown extension cords with three outlets? They’re usually 2 prong (don’t have a third prong for ground). They also don’t have any of the fail-safes that new extension cords do have.
While I was not specifically talking about daisy-chaining power strips, I wanted to make it clear that even using multiple extension cords in a daisy-chain manner adds significant resistance to the circuit and with enough push and a big enough amperage appliance it absolutely is a fire hazard.
I’m not sure where you got that I said you shouldn’t use an extension cord with a welder. I was saying you don’t need an extension cord worthy of powering a welder safely in order to power a lamp. But a smaller lower rated extension cord that works for a small indoor appliance is not up to the task and would be dangerous to use with a welder without the proper protections.
https://a.co/d/j4LCF4t
https://a.co/d/aZ3Nc8I
All devices are rated in both voltage and amperage. The reason the voltage is not typically listed is because the market defines the voltage available and the plug on the device is what tells you the device’s voltage rating, if nowhere else. It’s still important to tell you if it requires an adapter, ignoring the part where the average consumer isn’t going to try to wire a NEMA 5-15 (regular north American plug) to a 12v barrel plug.
This next part is not me trying to be a know-it-all, but to dispel an incredibly dangerous misconception. Amperage is not necessarily what kills you. That is a myth, and a dangerous one at that. Amperage is what causes burns, including internal burns, and is what kills you later at the hospital. Higher voltage is what kills you NOW by finding more paths. If it crosses your heart or brain, it’s probably over. Electricity does not seek the path of least resistance, but rather it travels across each path inversely proportional to the resistance. If you complete a circuit with opposite hands, you’ll probably be safe because your chest cavity of blood vessels will conduct the majority of electricity in paths other than through your heart or brain. AC power and higher voltages increase this risk. Low voltage is not entirely safer, but for most consumer use, “low voltage” is mostly below the breakdown voltage of dry skin, about 30-40v. Wet, and especially sweaty skin will conduct far lower voltages - licking 9v batteries is a normal example, but I’ve also been shocked by a 12v car battery the first time I worked around a side-terminal battery. Opposite forearms, too, so you can bet I took a minute to monitor my pulse. But the Lethal voltages and amperages are in the milli-unit range if they find the correct path. That’s not a high threshold, even with the significantly lower resistance pathways across your chest taking the majority of electricity. And, even if it was just amperage that kills you, you have no control over it because you’ll never know how much resistance you’re creating for the circuit to travel. It’s an unknown variable that’s supposed to be infinitely large but, if you’re getting shocked, it’s something lower than infinity. I household circuits, your drawn amperage will be much lower than the 15a circuit breaker and it won’t trip to save you. That is where GFCI circuits come into play by detecting incorrect electricity paths rather than amperage overload. 15a circuit breakers prevent fires. GFCI prevent death.
The funny thing is the breaker only costs $0.01 to include, but could prevent a house fire. Crazy we don’t demand it in all of our cords
British cables are fused in the plug, and it’s a pain in the ass. I don’t see the problem with a breaker that just drops the whole circuit if something goes whoopsie.
That’s just rephrasing what I said. You can plug in too much for a single extension cord even if there’s no chaining. A chain “just” increase the risk.
Yes but I was emphasizing the parallels to the USB c problem.
In USBC if you use a 200 watt cable that has 200 watts going through it and then extend it with a 15 watt USB c cable, the 15 watt cable will over heat.
If you plug a 30 amp load into a 30 amp cable and then extend it with a 15 amp extension cord, you will get overheating on the 15 amp extension.
You could also just plug in the 10 amp cord and plug the device into it. The chaining doesn’t change anything here.
I feel one would have to work really hard, with really shitty extensions, with really high amp draws to cause a problem.
SOURCE: I’ve temp wired some nutso shit.
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.
I would hope that a device capable of pulling 200w from USB would be intelligent enough to detect the excessive voltage drop and error out or reduce the current.
Extensions aren’t part of the official spec, so they aren’t actually certified as proper USB-C.
Same risks as any other janky no-name gear you see online, even if it SAYS it’s rated for a specific throughput or power rating, that may not be the case.
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This is what AI says about this video:
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.
Jokes on you buddy. Most people can’t afford houses these days.
But yeah, if you don’t know what exactly what you’re doing, err on the side of caution
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.
Idk man. If you’re writing wrong stuff, people will call you out here on Lemmy. Doesn’t really matter who you are. And the issue was someone wanting that info as text.
You’re a bold one. Lemmy hates videos and AI both.
Considering this AI answer is kind of wrong, can you blame us?
I asked the AI if it was wrong or you were wrong. It said you were wrong.
Who am I to believe?
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.
I’m sick of stuff that should be ~2 paragraphs of text being a video. I do not want to watch a person or hear a narrator, I interpret written information much more effectively, and being text I can retain significant portions of the document as necessary.
Strangers passing in the street
By chance two separate glances meet
And I am you and what I see is me
You know, you don’t have to watch it. You can find the information elsewhere in text format. But I guess we all need to conform to your preferences.
It’s nice that you’re so ready to delegate to my natural authority, but unnecessary.
Well I prefer the video. So make sure you watch it. Give a like as well.
The AI got most of it vaguely right, but unsurprisingly a lot seems to go above its head. Kinda like reading a shitty tech journalist writing about something they don’t understand at all.
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.