Benson Leung, an engineer on Google's Pixel team, was doing God's work by risking his Chromebook Pixel, which charges via USB-C, to test every single USB-C to USB-A cord available to general consumers. One crappy cord, and his $US1500 computer would be fried. You know how this story ends right? On Monday, a cheap cord purchased from Amazon destroyed all his testing equipment, including his computer. According to Leung's Google Plus page, the "SurjTech 3M USB 3.1 Type C to Standard Type A" cord was unbelievably poorly made, with some necessary wires soldered incorrectly, and other wires missing. (Mercifully, the faulty cable is no longer available for purchase on the site.)
While the SurjTech cable is the most destructive one Leung's tested, it isn't the only cord capable of damaging your devices.
This is USB Type-C.
If you use a cord that is Type-C to Type-C (with two connectors like the image above) you'll be safe. Both inputs draw very specific amounts of power and that's precisely what they should do. The damage to electronics occurs when they're pulling down too much power, or conversely, not enough power.
The problems start to arise when one end of the cord is the new Type-C input and the other end of the cord is Type-A -- that's the input we all think of when we think USB. Leung found that cords that were Type-C to Type-A were failing to regulate their power draw appropriately.
This is a USB Type-A connector.
Type-A was never designed to handle the 3 amps ("3A") of power a USB-C device needs to juice up. Nor was it designed to really regulate power draw like Type-C. The only way the two inputs can communicate effectively and safely is if they are constructed in a very specific manner, and unfortunately this can only be determined via vigorous testing or dissection of the cable.
The good cables that quickly and effectively charge your device will look just like the shoddy off-brand cables flooding Amazon and other markets. Leung does have one suggestion -- highlighted on his Google Plus page last night.
Avoid any cable that looks like this:
While thick braided cables usually scream "quality", this specific cable appears to be manufactured by a single company and re-sold by multiple other companies. He went on to say that he's found this specific cable sold by multiple companies and when he examined "the different variants of the cables from this common manufacturer, none of the variants are correctly configured".
In this case, there is a common manufacturer for the following brands that I can see on Amazon today :
If you're thinking about buying a cable to power your OnePlus 2 or Nexus 6P, then be especially wary of any from those sellers. And if you're curious about how good other Type-C to Type-A cords are, Reddit has created a helpful spreadsheet covering all of Leung's reviews.