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Comment by OnlyOneCannolo | Hacker News Reader

Is it really undetectable? A smarter USB PD controller and maybe some extra sensors should be able to mostly avoid that problem, no?

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Most devices of meaningful value build in USB-C port protection parts specifically for this reason. Here's a popular one from NXP: https://www.nxp.com/products/power-management/load-switches/...

"smarter" an "should" are key words.

Not everybody buys the best hardware in class. Most hardware is cheap Chinese garbage for which the only qualification is that it isn't bad enough to be brought down from Amazon.com.

Go explain your grandma or girlfriend why the charger they bought damaged their laptop irreparably.

Ok, so you detect voltage drop of say 0.4V@5A on the phone end, so slightly out of spec. How do you decide whether it's a slightly underspecced cable (quite common) and 2W being radiated as heat from a 1m long cable (which is not really an issue), or great cable but high contact resistance (where 2W are concentrated into a tiny space that can't cool it)?

You could design a port with multiple contacts onto the same cable pin. One contact does voltage sensing while the other takes the current.

Then any amount of dirt in the connector can cause whatever heating it likes, but the device can always calculate how much heat is being dissipated in the connector.

Nice idea. :) Thanks.

The cheapest option I see is a fusible link from some very low melting point material.

No, unless you put a sense resistor on every power pin, and add circuitry to individually measure current per pin.

If the alternative is starting house fires that sounds pretty reasonable.

The problem isn't whether reputable manufacturers will do it, it's whether the bottom of the barrel cheap cables from eBay/Amazon will do it.

The advantage of USB2 is that it's very hard to screw up. The design is so simple that even the cheapest cable is usualy "okay" because making an "okay" USB2 cable is so simple.

In contrast, making a USB-C cable is much more difficult, which means unscrupulous manufacturers flood the market with bad cables that fail with disastrous side-effects.

The solution would be for devices to test cables before letting them work.

If my iPhone tested the cable was up to spec before charging and said "error, bad cable" if any test failed, then china-cables would be forced to pass all the tests.

If the pin turns bad during use, you can't do much

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