I believe you would be best served to dictate to the electrician exactly what you desire, and only let him/her override you only if there's a threat of burning down your house.
IMO, Glen (the well-known electrician on this site) is very knowledgeable but is perhaps more the exception rather than the rule.
In my experience, if you should tell the typical electrician that a power cord, line conditioner, dedicated lines, etc., will improve sonic performance of your system, they will simply laugh or snicker.
In fact, some to many on this site will react the exact same way.
Based on the comments above, I'd stick with the tried and true 10 gauge OFC romex. But don't just buy the cheap 10ga at home depot. Spend $50 or $100 and get a 100 ft. spool of 10 gauge 99.95% OFC at a place like PartsExpress.com.
And while you're at it pick up some industrial duty 20 gauge wall outlets for about $20 a pop. danielwoodhead.com is suppose to have some fabulous ones for around $15 or $20.
And make certain that the electrician doesn't wire the circuits out of phase, etc.. (hot to hot, neutral to neutral).
For example: I had an electrician friend install a dedicated circuit for a few years ago. Later I went back to do swap in some audio-grade outlets. Had I not double-checked the outlet for power after tripping the circuit breaker, I would have had a nice jolt.
The electrician wired the dedicated line to the wrong 15 amp circuit breaker when it should have gone to the 20amp circuit breaker right next to it.