@dpop said:
Just to clarify, AC-HCF is considered better than EMT (see the chart on Middle Atlantic’s page 13). AC-HCF is considered a 1/2" (depending on gauge of wire) steel-clad MC.
I’ve posted about this before...
Actually,
The most effective way to reduce GVI is to twist the phase conductors together and pull through a conduit with a straight ground wire.
This may be time consuming and impractical, but for critical situations where millivolts matter, this may be the best solution.
Page 40 of your Web Link.
Ground Voltage Induction (GVI)
Non ("Isolated Ground) 3 wire MC aluminum armored cable is the way to go in my opinion. Easier to install than EMT conduit. Not to mention the time that would be spent twisting the Hot and neutral conductors together. Imagine a long run... With MC Code allows a plastic box can be used for the outlet instead of a steel box. A lot of audiophiles avoid using ferrous steel boxes. Some avoid ferrous steel conduit.
MC Aluminum Jacket
(best for non-IG runs)
See chart on page 40.
(FWIW, It beats me why anyone would install an IG receptacle in a house. )
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From page 13:
Armor Clad for Healthcare Facilities (AC-HCF)
Aluminum Armor Clad for Healthcare Facilities (AC-HCF) is the best choice for
Isolated Ground A/V systems. Like MC, it contains an additional grounding
conductor, although with this type of cable it is permissible to use the metal jacket
as the safety grounding conductor, as required with isolated ground installations.
The biggest benefit is that the average proximity of the hot conductor and the
neutral conductor with respect to the isolated equipment grounding conductor is
nearly equal, virtually eliminating ground voltage induction (GVI), even on long
runs.
Steel Armor Clad for Healthcare Facilities (AC-HCF)
Similar to aluminum armor clad AC-HCF, but does not address ground voltage induction as effectively as aluminum (see Ground
Voltage Induction section of this paper). Two other problems are that steel clad is not readily available and is cumbersome to transport
and install
/ / / / /
Side note:
For those that may choose to use conduit. Best practices for a true dedicated branch is a true dedicated circuit does not share a conduit or cable with another branch circuit.
.