New Electrical Circuit

@jea48 ​​​​​

Do you normally specify isolated ground and is that why you recommend MC?

@devinplombier

For a residential house I never recommend an isolated ground. It would not serve any purpose what so ever. FYI even in commercial and industrial facilities an IG, Isolated grounding conductor and IG type outlet are seldom used now days. They where big in the 1970s, 80s and 90s. They started fading in the early 2000s.

I recommend 2 wire solid copper aluminum armor MC cable.

Example:

10/2 Solid copper Aluminum armor MC (Metal Clad) Cable

The reason I like MC cable better than Romex is because of the way it is constructed. Hot, neutral, and insulated green equipment grounding conductors are tightly twisted together in a spiral twist and held tightly together by the armor. MC cable NOT AC cable (commonly called BX). AC cable is garbage for feeding audio equipment.

Romex is ok provided care is taken when installing it. Avoid twisting the cable as not to change, distort, the lay of the EGC (Equipment Grounding Conductor) between the Hot and neutral current carrying conductors. That’s next to impossible to do. If you tell the electrician to install the Romex keeping the cable flat without any twists. He will think you are nuts...

Read pages 12 and 13. Note the chart on page 13.

Integrating Electronic Equipment and Power

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@jea48 

Thank you, that makes sense.

Between (a) running 3 separate homeruns to the panel as mentioned above, and (b) a single homerun powering a subpanel in the listening room, which would you recommend?

@jea48 My electrical box is outside. Can they encase the (Southwire Armorlite 125-ft 10/2 Solid Aluminum MC (Metal Clad) Cable) inside metal conduit for the outside portion for weather proofing?

@puffbojie

My electrical box is outside. Can they encase the (Southwire Armorlite 125-ft 10/2 Solid Aluminum MC (Metal Clad) Cable) inside metal conduit for the outside portion for weather proofing?

Not really.

The electrician can use a, (example), EMT to AC/MC/FMC/NM Transition Fitting . He will remove the aluminum armor for the length of the EMT conduit and the wire needed for make up in the electrical panel.

Or he can use a junction box inside to transition from EMT conduit box connector to an MC cable box connector. I think the EMT to MC transition fitting would work better, jmho. Your electrician on the job site will know what will work best for him for his install situation.

If you decide to have MC cable installed make sure the electrician installs 3/8" anti-short bushings on all cut MC armor ends. Anti-short bushings are not required by NEC code. Have him install them anyway... They protect the insulation on the conductors from the sharp edge of the armor.

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Between (a) running 3 separate homeruns to the panel as mentioned above, and (b) a single homerun powering a subpanel in the listening room, which would you recommend?

@devinplombier

Not a simple question to answer. Best answer I can give is, It depends.

How long are the home runs? How many branch circuits will be installed? (You mentioned 3)

Cost of a good sub panel and feeder to feed the panel ain't cheap.

As for where the sub panel will be installed. I read occasionally where the panel is installed in close proximity to the wall outlets being fed. By close I mean less than 25ft of wire. Jmho that defeats one of the reasons for installing multiple dedicated branch circuits. To decouple audio equipment AC power supplies from one another. Not much impedance and inductance in 15 to 25ft length of wiring.

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