Hi,
some points:
* the copper needs to be thick enough not to burn. Look at least for 0.25 mm^2
* you need to decide what max. voltage drop you want. Maybe max. 1.0V. 1.0V at 2.7A means 0.37 Ohms. Now it depends on length of wire: 1m of 0.25^2mm cable has about 2 x 70mOhms = 140 mOhms of resistance. So it´s good for 2.6m cable length.
* it must be very flexible.
* it shouldn´t be too thick (over all)
* it should be chemical resistant (flux, especially)
* maybe it should be shielded ..
* maybe it should be electrostatically dissipative. (ESD compliant)
Klaus