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by Spooky23 2380 days ago
The author makes the valid point that USB-A is too low power, and USB-C requires active cables. (Translation: expensive or dangerous)
3 comments

USB-C doesn't require active cables. Only 100W USB-PD and longer high speeds require active cables. The marker chip for 5A charging cables is cheap.

Both USB-A and USB-C chargers require active logic. USB-C is more complicated because includes both USB-C and legacy USB logic. USB-PD is the most complexity.

USB-A can support power delivery. The standard predates USB-C.
In practice I haven't seen USB PD 1.0 in the wild. Most of the non-PD charge standards signal charge rates using varied voltages on the D+/D- lines.

When current manufacturers claim USB-PD they mean PD 2.0 which requires the CC line (Only included in usb-c to usb-c) to signal and set the voltage. When PD 3.0 is included, they usually call it quickcharge 4.0 or PPS.

If you want one port that can charge multiple devices of varying needs safely, you need smarter cables. Sounds like a reasonable tradeoff.

Otherwise every single cable would have to be built to handle the highest possible power delivery rate (100W for USB-C).

Looking at that plug and how chunky the holes are for ac power, when access is limited and you can’t see, shoving a usb c plug into the ac hole is going to happen often.
You'd have to shove awfully hard -- hard enough to crumple the metal shell of the USB connector, since it's wider than the opening in 120VAC socket. (I just tried it with a spare electrical outlet, and even with a fairly hard push and wiggling it around, I couldn't make it fit)
Yikes and thanks - I’m in New Zealand and our plugs are way smaller so you couldn’t make that mistake here, but it’s good to know the terminals are far enough in that it’s safe. I’ve seen some surprising things people have forced into the wrong port. USB into Ethernet etc.
The long vertical slot you could come in contact with is neutral. The bottom peg is ground. The top right vertical strip is hot but it also has recessed connectors and is smaller than the usb c connector.

I'd be impressed if you could cause a short on purpose with significant force let alone fumbling in the dark.

The problem lies in that you're pushing the problem into the hands of anonymous cable makers and clueless end users. It's really difficult to stick a standard plug into a 30 amp socket.

It's really easy to buy some substandard USB-C cable that lies about it's capability.

The same issue would exist with any universal in-wall DC power supply -- if consumers buy a substandard product, it can destroy their device. Unless you want separate ports different voltage/power output then the user has to buy separate cables for each one.