Designer in wall wiring - worth it?

@jea48 IF Romex (NM Sheathed Cable) is used DO NOT deliberately add twists to the cable. Twisting the cable will change the Lay, design/construction, of the three conductors. Specifically the relationship of the equipment grounding conductor that is centered between the Hot and Neutral Conductor. (Two conductor with ground Romex)... 

Again the control of an induced voltage on the equipment grounding conductor from either of the two current carrying conductors. IF the equipment ground is kept centered in the middle of the Hot and neutral current carrying conductors the magnetic fields cancel one another out in the center of the two. The ground wire is said to be in the Null Zone, between the two current carrying conductors. 

@zlone said:

A very good point. There are so many subtleties to proper house wiring that most DIY’ers are not aware of because they are not obvious and have been learned over decades of establishing standards. Some of these represent real risks. 

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My response:

The quoted material from my post above is part of Best Practices for the installation of branch circuit wiring to feed audio equipment. 

You don’t want any voltage, (and with voltage there can noise), on the safety EGC, (Equipment Grounding Conductor), of the branch circuit wiring. 

What difference would that make for a piece of audio equipment that uses the EGC if there is a small voltage and or noise on the EGC? The EGC is solidly connected to the metal chassis of the equipment.

In some fashion the audio equipment electronics designer  connected the circuit signal ground, and the B- of the power supply, to the connected  EGC grounded chassis. That’s not a good thing if the EGC has a slight, small voltage or noise on the grounding conductor. You don’t want either to get into the audio equipment signal path.  

Where more than one dedicated branch circuit is used to feed audio equipment, connected together by wire interconnects, a small voltage on the EGC in millivolts of any dedicated circuit can cause a ground loop hum. 

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As for a residential house wireman, or even a journeyman inside wireman for that mater, they could care less about if any twists are in the Romex as they install it. They do watch for sharp bends or kinks.  They also could care less if dedicated audio branch circuit  Romexes are pulled closely together above ceiling truss members. Or ran in close proximity of LED and dimmer control branch circuit wiring. Induced voltages from one cable to another or noise transfer from a cable to another/others is not a concern to them. That's not even on their mind.

Does the light turn on when the wall switch is flipped on? Are all the wall outlets hot with the correct AC polarity and EGC shows OK not OPEN GROUND. 

As for following Best Practices for installing electrical wiring to feed audio equipment, the average licensed electrician, would just roll his eyes. A residential house wireman would probably just look at you. Hey, it’s just Romex. 

 As for electrical safety codes. They could care less how an audio system sounds. Is the electrical wiring and installation safe?.

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2023 Code Language:

N 90.1 Scope. This article covers use and application, arrangement, and enforcement of this Code. It also covers the expression of mandatory, permissive, and nonmandatory text, provides guidance on the examination of equipment and on wiring planning, and specifies the use and expression of measurements.

90.2 Use and Application.
(A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazard arising from the use or electricity. This Code is not intended as a design specification or an instruction manual for untrained persons.

(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion or electrical use.

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