My new MacBook Pro came with a USB C charger and an associated cable.

I'm noticing this cable is a little bit thicker than other USB C charging cables I've seen.

What safety and charge carrying standards exist with USB C so I can know if a specific thinner / thicker cable is both safe and can support specific charge rates?


To answer my own question, according to Wikipedia, USB C cables can have different carrying capacities:

All USB-C cables must be able to carry a minimum of 3 A current (at 20 V, 60 W) but can also carry high-power 5 A current (at 20 V, 100 W).[10] All USB-C to USB-C cables must contain e-marker chips programmed to identify the cable and its current capabilities. USB Charging ports should also be clearly marked with capable power wattage.[11]

So while I can't say this with 100% certainty, the cable that comes with the MBP charger probably is a higher capacity cable, but USB-C cables have chips in them to tell the device and charger their carrying capacity.

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The fact that the cable is thick does not necessarily lead to it's ability to reliably deliver a higher wattage. A thinner cable will deliver as much power as long it's a good quality cable that adheres to USB-C standard. USB-C is a standard, but that doesn't mean that all cables you can buy adhere to it. You could buy a thick cable that is poorly made and it could be a hazard.

The thickness of the cable doesn't really matter. It's the quality of the cable and how well it adheres to USB-C standard. When buying USB-C cables, buy from a reputable brand and for more than $.99

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  • A thicker cable can mean a thicker inner shield, thicker protective coating, or both. This translates to longer life and durability. – IconDaemon Jun 24 '19 at 21:59
  • Absolutely, a thicker cable usually does indicate a higher quality for the reasons you mention, but the thickness of the cable doesn't inherently mean it's better. – clbx Jun 25 '19 at 13:03

Don’t confuse the USB-C connector with cables that are actually dual purpose. A thicker cable almost always signifies an active cable that supports both high USB PD charging and Thunderbolt 100 W power carrying capacity.

The shielding needed to allow 40 Gbps on Thunderbolt 3 / USB 4 is likely the reason Apple’s cable is beefier than others that are designed for lower power and less data of USB-C 3.x.

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  • This is incorrect. The signal to look for that indicates an "Active" rather than "Passive" Thunderbolt 3 cable, is the longer connectors on the end of the cable. The connectors are about 3cm long on the active cable. In many cases it will be the same thickness as a thinner, passive Thunderbolt 3 cable. Either type of Thunderbolt 3 cables should also have a lightning arrow and a "3" printed on the connectors. – Neil Apr 28 at 22:46
  • Hi @Neil thanks for the comment. Which thinner cable that comes from Apple is active and which Apple cables are thicker and passive? I’d like to understand how I got this wrong. Are you able to help me understand which thin cables do a better charging job than the thick ones Apple provides? – bmike Apr 28 at 23:34
  • The "Active" and "Passive" options for a Thunderbolt cable pertain only to their ability to transmit Thunderbolt 3 speeds over a long length. For short cables, Thunderbolt 3 speeds can be achieved over a "passive" cable, for longer cables, only "active" version can do Thunderbolt 3 speeds. For even longer cables, they need to be "optical" cables. @bmike It seems like you just want a cable that can carry 100W of power. Usually the product page of any USB-C or Thunderbolt cable will say how many watts it can handle. Remember that Wattage = Amperage * Voltage. – Neil May 6 at 19:07

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