Hi,
Why do you expect the cables become hot?
Hot because of DC power dissipation?
--> P = I^2 × R.
If it be ones hot, then either I is too high, or R is too high.
There is a USB specification that takes care about I and R. It tells what wire gauge one needs to use fir an USB cable to get low R.
And it tells how to protect against overcurrent...
Additionally, why do you expect current flow at all ... when all laptops are self powered. I assume none of the laptops will draw it's power from the USB...(while this theoretically may be possible with USB 3.0)
****
But I wonder:
* why are 3 laptops involved?
* why USB?
If you run Excel on all three laptops to process the data, then the bottleneck will be the I/O handling and parsing of the incoming data...
I assume here Excel doesn't provide good performance.
Why don't you use LAN, WLan, WiFi or bluetooth?
Klaus