Yeah, I'm confused about the Data Cable also. From reading Appendix B of the HPWC manual, they say... The signal wire should be in it's own 1/2" conduit. If you run the signal wire in the power conduit, the insulation rating of the signal wire should be equal or greater than that of the power wires. (I have no idea how to check that.) They also say to use twisted pair, and recommend shielded cable. As a network / infrastructure wiring consultant, I deal with network data cables a lot... Firstly, we can easily get Cat6 Shielded Twisted Pair cable, but the HPWC only uses 1 pair, whereas a network cable contains 4 pairs. I have seen many people "double up" these cables to make a "better connection" but that is now how twisted pair works - the whole point behind twisted pair is that the send and receive pairs are twisted together, so that the crosstalk between the two is neutralized. If you use the white/orange, orange/white pair alone, you will get better signal than if you use both orange cables in D+ and both brown cables in D-. Secondly, the shielded cables need to be connected/grounded to something or the EMI will produce the same interference in the shield, that will then be transmitted to the signal pair. There is no ground in an HPWC, only a neutral, and I don't think we should be connecting the STP cable to that. SSonnentag did a great job of routing the data cable through a separate conduit, which I think is overkill, but certainly will get the best results. Last dumb question. The instructions say to set the rotary switch to "1 to 8" on the master, depending on the amperage of the circuit. That only allows for a 50A circuit, as anything higher uses "9 through D". I'm hoping that this is just a typo.