Dedicated 20 amp circuit. 10/2 or 10/3?

Considering the cost of copper, etc., the materials cost of your project are not exactly cheap but the labor is probably more expensive.  It will be easier to run both lines at the same time, which should reduce your labor cost compared to running one and then deciding later you should have run two.  I have three dedicated circuits to my audio area and all three are on breakers next to each other on the same side of the panel.  I do not regret using 10awg wire, even though the circuits are each only 20A.

That's my other question.  Which side of the panel should I use? And should I place all my dedicated circuits on the same side?

Lets think about why a dedicated line was conceived and what it is used to achieve. A dedicated line does the following in my mind:

1. Ensure that your audio system has more than enough power to handle a big amp pulling pulses of high current for bass notes and dynamic sections.

2. Ensure that the circuit is not shared with noisy items like washing machines etc with motors that start, lighting circuits that may have noisy dimmer switches, large resistive devices like hair dryers, irons, and heaters that can impact the shape of the sine wave, etc.

Note that we aren’t trying to protect the audio system from other things on the audio system. Exceptions might be: cheap power supplies for accessories such as ethernet switches, TV, TV streamers, wifi mesh hubs, etc. That is why I thought maybe you want to put in 2 lines, one for pure audio equipment and one for potentially noisy support stuff.

But I’m not convinced of the value of putting in dedicated line for each component. I guess it won’t hurt but I didn’t do it and I wouldn’t do it.

Effectively you’re moving the node where all the stuff ties together from the outlet behind your audio system to the breaker box, perhaps 50 ft away.

Jerry