Club 3D Unveils PD 240W USB Type-C Cables

[DeathtoGnomes]

The resistance in the cable is the same (given the same-ish cable)

Resistance is insignificant per foot, its actually measured per 1000 feet, we're talking less than .1 ohm per foot. I'm gonna guess that there is 28 guage wire wire in these cables, that works out to about 65 ohms per 1000 feet. Most commercial use wire is not pure copper anymore. That plus the size of wire, and length, temperature affect resistance, but its still minimal.

Current affects wire moreso than resistance, its movement causes the wire to heat up, and increases resistance, BUT it still does not affect resistance as much as you are implying. Which is why only load is measured in a circuit.

 

[trsttte]

Resistance is insignificant per foot, its actually measured per 1000 feet, we're talking less than .1 ohm per foot. I'm gonna guess that there is 28 guage wire wire in these cables, that works out to about 65 ohms per 1000 feet. Most commercial use wire is not pure copper anymore. That plus the size of wire, and length, temperature affect resistance, but its still minimal.

Current affects wire moreso than resistance, its movement causes the wire to heat up, and increases resistance, BUT it still does not affect resistance as much as you are implying. Which is why only load is measured in a circuit.

That's not the point, of corse the cable won't heat in any significat way because external power supplies like the ones laptops use need to meet mandated efficiency targets of around 88%, that wouldn't be feasible while heating cables as short as they may be.

The point is someone was saying the 48V will cause heat problems: it won't, it's still the same 5A from the previous version of the PD spec (100W @ 20VDC 5A).

Now to your specific answer, the current won't affect the resistance, that's a property of the physical material. The current will just heat it and waste a very tiny ammount of power while doing so (Ploss = R*I^square as Joule would say).

 

[DeathtoGnomes]

Breakdown of insulation, too small of wire, too much current, or too large of load?

You choose.

 

[Valantar]

Breakdown of insulation, too small of wire, too much current, or too large of load?

You choose.

Aren't the latter three essentially the same, just depending on your chosen perspective? Breakdown of insulation seems unlikely given the extent of the damage - in my experience that will cause a more focused hotspot where the insulation fails, and rarely spread like this. This looks like a significant portion of the wire has heated up way past the melting point of the plastic and into combustion territory. This wire wasn't by any chance marketed as one that would light up?

 

[pavle]

I demand a 900 Watt USB-C cable!

 

[Valantar]

I demand a 900 Watt USB-C cable!

180VDC 5A?

 

[R0H1T]

I demand a 900 Watt USB-C cable!

JHH will ship them with the latest & greatest TitanZ TitanicZ ~ only 10 grand a piece

 

[trsttte]

I demand a 900 Watt USB-C cable!

180VDC 5A?

Small devices use two-prong USB-AC, but there's also a three-prong version with a USB-B plug as the ground.

 

[DeathtoGnomes]

Aren't the latter three essentially the same, just depending on your chosen perspective? Breakdown of insulation seems unlikely given the extent of the damage - in my experience that will cause a more focused hotspot where the insulation fails, and rarely spread like this. This looks like a significant portion of the wire has heated up way past the melting point of the plastic and into combustion territory. This wire wasn't by any chance marketed as one that would light up?

Yep they can be lumped together. The fact that a length of wire heated says, to me atleast, that there were no weak spots in the wire. Flaws during manufacturing can create a weak spot, like a notch where insulation is thinner, or where the wire might have been exposed or even stretched accidentally. They imperfections could result in a hotspot BBQ instead of a spread like that. Yea I see that as a slow burn, current rises slowly enough the whole wire is affected.

 

[Dredi]

180VDC 5A?

I wonder what the actual insulation related limits are of typical USB-C connectors (not the cable), i.e. what is the max voltage before an arc happens somewhere. The pitch for the smd pads used in usb-c connectors is pretty tight.

 

[pavle]

I wonder what the actual insulation related limits are of typical USB-C connectors (not the cable), i.e. what is the max voltage before an arc happens somewhere. The pitch for the smd pads used in usb-c connectors is pretty tight.

Well, just measure the distance, over 1mm (0.0394 inches) 1000V is needed to arc over the air, so says the classic rule. Otherwise depends on insulation/conductivity properties of the material in question.

 

[Dredi]

Well, just measure the distance, over 1mm (0.0394 inches) 1000V is needed to arc over the air, so says the classic rule. Otherwise depends on insulation/conductivity properties of the material in question.

Yep, so with some basic Mitsumi connector we have 0,23 mm space between the pads, so with perfect soldering and no insulation fill we get a maximum of around 230 Volts. Safety margin of 2 cuts it to 115 V. Plenty of room to get more watts through