About Grounding

Grounding is a key component of any electrical installation.  If for any reason else, a proper ground will route a lightning strike away from electrical components in your home and safely to earth.  If for no other reason, you want an optimum ground to protect your assets. 

Grounding is a misunderstood concept. Many people think a good ground is a way to shunt noise to earth. I have heard a well grounded system lend a sense of calm and ease to a room, a felt presence. I have also heard a well grounded system allow much better integration of bass and mid/high drivers. But is it the ground rod in the yard doing the heavy lifting, or is it the way the ground system throughout the entire electrical infrastructure is applied. I find it more the later. Don’t get me wrong, a good ground to earth of less than 5 ohms is critical. But controlling the voltage potential between grounds throughout the system is critical to a noise mitigation.

From Bill Whitlock:

A Real-World Example.  Assume 25-foot, foil-shield cable with #26 AWG drain wire. R = 1 Ω.  Assume leakage current between 2-prong (ungrounded) devices is 316 μA.  Noise voltage = 316 μV.  Consumer reference = 316 mV.  S/N ratio = 316 mV/316 μV = only 60 dB.  Belden #8241F cable, shield R = 0.065 Ω, would improve S/N by some 24 dB!

From Bad to Worse ...When devices are grounded, often via other system cables, noise can become EXTREME!  When ground voltage difference of only 30 mV between outlets is impressed across length of cable, resulting S/N becomes only 20 dB.  Huge problem in home theater systems having multiple ground connections – sub-woofers and projectors with 3-prong plugs, CATV, and satellite TV connections.

What does all this mean. It means the relationship between ground, neutral, feeders and branch circuits is critical. It means the selection of conductors and how they are installed is critical. It means your fighting noise throughout the entire chain of power. For me it means hyper attention to detail when it comes to how you install conductors. It means one ground with all sources referenced to it, and only it. It means all paths back to the ground source need to be neat, strait, unbroken, uninterrupted, direct and applied in a star configuration. The best system you can build is based upon 1 branch circuit, 1 receptacle.