Running a dedicated A/C circuit

I would avoid introducing any ferrous materials into your circuits.
Aluminum, zinc, copper and brass are non magnetic.
Stainless steel, if non magnetic, is also good.
That includes boxes, connectors, screws and raceway.
BX has been replaced by MC cable, I won't go into the differences.
If you must use MC, specify aluminum, instead of steel clad.
I am not a fan of shielding everything, it can choke dynamics to death.
On the other hand, I am constantly experimenting with resonance damping. (DIY quartz products)
When you hit on it correctly you can hear the improvement.
Over do it and you'll shut the dynamics down.

I just obtained some mini Amethyst in bulk.
There was a "bulk" amount of black Tourmaline powder on Ebay, but it was way more than I wanted to purchase.
Supposedly, it is used in therapeutic baths.