Hum in Speakers with New Dedicated 20 amp Circuit

Edit to my above post. 🔼 🔼 🔼

Looking at the photo again this morning of the feeder conduit entering on the left side of the panel it may very well be PVC conduit. Not metal conduit. If that is the case the OP should not move the EGC ground wires to the ground bar on the left side of the panel.

I based the possibility the feeder conduit may be PVC by looking at what can be seen of the connector’s color of the threads and the poor image of the connector on the outside of the panel enclosure. I also based my possible conclusion on the 50A branch circuit load conduit exiting the top right side of the panel is PVC. 100% sure the feeder conduit is PVC? NO... Without knowing for sure it would be bad advice, imo, to move the EGC ground wires to the ground bar on the left side of the panel.

IF the feeder conduit is PVC the ground fault current path is to the feeder neutral bar/conductor. Moving the EGC ground wires to the ground bar on the left side of the panel, the ground fault current path would be through the panel metal enclosure to parts of the touching places where the bare aluminum feeder neutral conductors is in poor contact with the panel enclosure. A very poor low impedance connection to say the least...

Looking at the photo again this morning of the feeder conduit entering on the left side of the panel it may very well be PVC conduit.

I concur looking at the color, saturation and reflectivity of the visible threads. It's a very close match to the PVC exit.

Just returned from a long trip.  Want to thank everyone for the useful info.  I'm sorry I was not able to post more detailed pictures sooner.

Here are detailed pictures of both panels.  The conduit between the panels is indeed PVC.

Let me know if your thoughts.

@mjjw

It’s an easy fix for a licensed electrician.

Replace the bare Aluminum neutral conductor with an insulated #2 AL conductor. (Code required for a sub panel)

Install a new #8 copper green insulated equipment grounding conductor. He will terminate it on the ground bar in the sub panel. (Could be #8 bare solid but stranded is easier to work with. He’ll use a piece of green stranded #8cu insulated wire.

Move the equipment ground wires from the neutral bar to the equipment ground bar. (Extend wires as needed)

I would have the electrician check the System Ground, Grounding Electrode System, (Electrical Service connection to Mother Earth), to make sure it meets the code for your city.

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