Electrical Panel Grounding


Beyond electrical code requirements, why does the sub panel earth ground, with its own earth ground, need to be tied to the main electrical panel ground?
wgutz
Wguts, none of this is necessary nor will it improve anything.

What matters is that it all be referenced to a single point, where the neutral is bonded to it. Putting in a single, or 20 ground rods won’t help this at all.  Follow the NEC, and local codes which may now require 2 rods.

I’d focus on your room acoustics. :)

The point of the ground is to act as an earth safety, which it can only do well if bonded to the neutral at 1 location.

Now if you want to run isolated grounds from the panel, that's fine.

Thanks Eric:

As an audiophile, we have had success in the past with using a ground field (multiple ground rods). My associates include a satellite engineer who made the original suggestion. I believe I have a audiophile grade system. I am using Sounlab U-2 electrostatics driven by 6C33C power tubes.

Since you brought up room treatments, I work on this every weekend. One question you may know the answer to is regarding 2" square wood block diffusion panels. While using longer pieces of 4" and 5" I understand this will increase the octaves covered over 1", 2" & 3". But what discernible sound effect would this have? it sounds to me as is there is some additional blurring in the mid-range.My focus is to tame some high frequency hardness.
High frequency hardness can be caused by local RF affecting signal via unshielded ICs and speaker cable (think Kimber, Nordost).
The earth does not possess some magical mystical power that sucks nasties from an audio system.

The main purpose for an electrical service connection to earth is for lightning protection.

You can fill your whole yard with driven ground rods if you like as long as they are all tied together and connect to one point to the main electrical service entrance neutral conductor.

NEC Code says the equipment grounding conductor for a sub panel shall installed in the same raceway, conduit, or cable assembly, as the feeder conductors feeding the sub panel.

The purpose of equipment grounding grounding conductor is provide a low resistance path for ground fault current to return to the source in the event of a ground fault event. THE EARTH IS NOT A LOW RESISTANCE PATH . When a sub panel is used the source is the main electrical service panel where the sub panel feeder equipment grounding conductor is connected to the service entrance neutral conductor. IF the ground fault current is greater than the breaker handle rating the branch circuit breaker in the sub panel will trip open breaking the ground fault circuit. IF the ground fault current leakage, due to a high resistance in the ground fault circuit, the circuit breaker in the sub panel just sees the ground fault current as connected load.

NEC code does allow an auxiliary grounding electrode to be connected to the equipment ground bar in a sub panel in addition to the feeder equipment grounding conductor.
IN ADDITION TO. NOT IN PLACE OF. I would not recommend it though. Lightning will travel through any path provided from the earth back to the earth. Especially a low resistance path.

Here is a great white paper for you to read.
https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

wgutz,

A mix of diffusion and absorption is always a good thing!

High frequency hardness is a funny thing. While a lot of people focus on 1st  and 2nd reflections, this can also be treated by generally adding absorption in the room. In other words, some of the problems are due to direct reflections, but some are just doe to how slowly or quickly it takes signals to decay.

You can experiment cheaply with throw rugs/blankets and putting other soft, absorbent materials on the walls. If that takes you where you want to go, then you are going in the right direction.  Also, don't neglect the ceiling!

You may also experiment with toeing speakers outwards so you are not in the direct line of fire of the tweeter.