Both sets of the compatible surround speakers for the Soundbar 700 are already hardwired only. The wireless communication is between the soundbar and the speakers so you don't have to run speaker wiring throughout your set up. However, the surround speakers do still need to be connected to an AC power supply. The speakers plug into a receiver, which in turn is plugged into the mains power supply.
If I have misunderstood your question, I apologize and look forward to clarification if so. If you also have any questions, feel free to get back to me. 🙂