Surprising findings inside USB-C charging cables!

Couple of days back I had posted about USB-C and USB-C PD (Power Delivery) cables and mentioned that though they have 24 pin connectors, they have only 16 wires inside. Today I decided to have a look inside a few USB-C charging cables which I had been using for charging mobile phones, but had been damaged over time. A great surprise was in store for me. Let us have a look inside those USB-C charging cables which were being used till a few weeks back.

It was easy to have a look inside this connector because it had split spontaneously and I was using a tape to keep it in position. All I had to do was to remove the blue tape and carefully open the metallic covering inside to expose the wires and shielding inside going to the type A connector of the cable meant for the charger end. There are four wires – red, black, green and white, covered by a braided shield. As described earlier, red and black are for the power lines and green and white the differential pairs for data. So it was quite surprising that the other 12 wires were missing in this cable. May be because it is just for charging purpose, all the other wires for high speed data transfer and configuration channel are not needed and this is a simplified version.

This was an even more simplified version, just two wires inside, one red and another white. No form of shielding was seen over the wires. As there was no option for data transfer, obviously there is no need for shielding to prevent noise and crosstalk, meant for data channels. While using this cable, there is no chance for the source to negotiate a higher rate of power transfer by communicating with the sink as is done in modern USB-C PD or power delivery cables which are capable of using higher voltages to transfer power at a rapid rate. This cable can just transfer power in an uncontrolled fashion, presumably at the 5 V 3 A rate of legacy USB ports, with no type C port protection at all. This cable was thin compared to other cables I have seen.

Next cable which I opened up is this one and you can very well see a braided shield covering the wires inside. This cable was thicker than the previous cable which I had shown just now. If you look carefully, you can also see another covering inside the braided shield, made of a thin metallic foil. I have seen similar foils in coaxial cables which I have opened up for crimping connectors in my amateur radio operations.

Now I have twisted the braided portion and kept it at right angles so that the metallic foil can be seen covering the wires inside. This clearly shows the two level shielding in this cable, which I expect to have data lines inside.

The metallic foil has also been separated to show the four wires inside. The specialised high speed data lines are missing in this cable as well. But there are two data lines, green and white wires as in legacy USB cables.

Four wires have been separated, to clearly see the white and green wires for data and red and black wires for power. If you look carefully, you can see some other fibres, other than the braided shield and the aluminium foil, which appeared to be nylon like material. We will check out whether they are conducting or nonconducting in the coming few steps, to make sure whether they are metallic or non-metallic.

Multimeter with its connection cables and a pair of wires with crocodile clips are being used to check the continuity of the outermost metallic braid and it can be seen that it is conducting material indeed. This is not the small nylon like fibres shown along with the wires.

Next the nylon like fibers were checked for continuity. There is no continuity, which confirms the initial thought that they are non-metallic.

Now the metallic foil is being checked, confirming its conductivity. So there are two levels of shielding for the data wires inside, meant for prevention of crosstalk and reducing noise pickup. Still even this cable is not the typical USB type-C cable which I had read about, with a 24 pin connector and 16 wires inside meant for configuration channel, high speed data and so on. I do have other USB type C cables here, being used for high speed charging of mobile phones. But as they still functioning well, I cannot open them up to see if they have more number of wires. I will have to wait till they get spontaneously damaged, to have a look inside.