power cord directionality

That is the exact question I’ve been asking on many different threads here for a very long time for the last few years. No one seems to know, or if they do they’re not sharing. It’s similar to the question, why does the effect of vibration on cables and wire like tonearm wire change the sound? It has to do of course with what is the “audio signal” through wire and how does the signal become distorted? I have even offered prizes to the winner. Share, share!

@optimize please reD my posts again..this is a custom umbilical btwn power supply and preamp..
@jetter as this is a custom job, the directionality  is indeed indicated by a label placed on the cord. 

Further follow up for those interested....here is the explanation of how the umbilical is electrically tested, so it couldn’t be backwards, just accidentally labeled backwards...

Three aspects establish the directionality of my designs.   The aspect I refer to that is electrically testable is a bonding test, an in-process electrical test whereby electrical continuity is verified of the internal shielding within the outer conduit to the metal shell of the connector on the power supply end of the cable.  In my designs the internal shield systems of the cable are drained (wired) only to the power supply end for reasons of increasing performance by enabling any electrical noise absorbed by the shields to be transferred harmlessly away from the music (away from the main preamp chassis). Secondly, and equally crucially, directionality is also established by paying regard to the directionality indicated by the manufacturer of the raw bare conductor. This directionality is stringently retained throughout the assembly process.  Finally, the audiodharma Cable Cooker has a directionality of its output signal, and the connections on the Cooker are marked respectively.  
Thx for those that have been interested 
j

If you're not getting ground loop noise then it doesn't matter. The only reason for the arrow is if they lifed a shield on one end in an unbalanced wire. Yours is balanced with the three pin XLR the arrow is irrelevant.