If you are after sonic improvements, simply have the electrician hook up the romex as he would to meet code. Then after he's done, disconnect the ground at the wall outlet. Then, when you move, you can simply reconnect to meet code. For whatever reason, the ground has a way of introducing A/C noise into your lines and into your sonics. Not to mention ground loop hums, etc. The ground usually is connected to the same service panel bus as the neutral anyway.
You might want to ask the electrician to connect the new dedicated circuits so that they are on the same phase of 115 volts (You should have 2 seperate lines/phases of 115 volts going from the pole to your service panel). I moved my amp circuit from the opposing phase of my other dedicated audio circuits to the same phase and my amplifier's transformer hum went away immediately. AC noise affects much when it comes to grounds and audio equipment running on opposing phases.
Some will advise against grounding spikes, others against grounding to drain or cold water pipes, etc., etc.. Some reading materials and white papers on these subjects can be found at equitech.com and psaudio.com.
-John