Using the wrong USB-C cable can damage your tech. Here’s how to avoid that

Okay, here's what you need to know up front: 

• When in doubt, use the cable and charger that came with the device.
• Buy good quality cables from name brands such as Anker.
• If any cable starts to get overly warm or displays any issues, stop using it!

USB-C seems to have become the default for both charging and data transfer. And that's with good reason — USB-C is very versatile, currently allowing for power transfer up to 100W and data speeds of 10Gbps.

But the biggest confusion for the end user is that, well, every USB-C cable looks like any other USB-C cable, and every USB-C port looks like any other USB-C port. 

But not all ports and cables are made the same.

For example, your smartphone might come with a 20W USB-C charger and a cable that's good for that load.

But what happens if you connect that cable to something like Apple's monster 140W USB-C charger? Or some random 100W USB-C charger that you bought?

And then you use that cable to connect your laptop to that big power supply.

This is where USB-C gets messy.

The problem is that the complexity of the versatility of USB-C is hidden behind ports and cables that all look the same to the average buyer.

It's a bit like HDMI. It's hard to know what cable you actually need.

But unlike HDMI, it's a lot more difficult to buy USB-C that can handle everything.

This is where E-Mark was supposed to help.

This is one such tool, the AVHzY C3 USB-C tester. This tool is easy to use — just supply it power through one USB-C port, and connect the cable you want to test to the other port and it'll tell you if the cable has a chip.

Here is the C3 tester identifying a cable with an appropriate E-Mark chip:

Here's another:

This cable falsely claimed to have an E-Mark chip.

Another way you can tell is if you have a power bank that has a meter that shows volts and amps outputted and can output 100W, along with a device that you know can draw 100W — such as a laptop — you can plug the power bank to the laptop using the cable and watch the power draw.

If it draws 20V at around 5A, that's 100W. 

If it's 20V at around 3A, that's 60W.

Finally, a MacBook will tell you how much power is going into it. Click on the Apple icon on the top-left of the screen, then on About This Mac. From there click on System Report… and then click on Power in the left-hand menu.

Wait, so it's possible to cause damage using the wrong cable?

In an ideal world, no. USB-C devices have safety features built into them that that should prevent this from happening.

However, I've seen things go wrong, maybe because a device was defective, maybe it was poor quality to begin with, or maybe something went wrong in the logic somewhere and something crashed. But things can go wrong, and the results can be ugly:

• Overheating cables
• Overheating devices
• Possible battery damage from overcharging (this is rare since most batteries have separate charge controllers, but cheaper devices might not)
• Risk of fire from overheating or overcharging

Sure, these are edge cases, but do you want an edge case like this happening on your bedside table? I don't.

This is why I prefer to play it safe and use either the cables and chargers that come with a device, or buy high-quality cables that I know are up to the job.