Mains sockets and star earth - can anyone explain?


The vendor of my mains isolation strip advised me the following by email:

To avoid any unwanted grounding problems and to get the best performance out of your system you should power all electronics of your system, no matter if they are wired with or without a grounded cable  out of one wall socket (starred earth reference)

Can anyone explain what this means, especially with reference to starred earth?

I now have my amp plugged directly into one socket of my 2-socket wall plate, and my isolation strip (for my sources) plugged into the other socket.  What difference does this make to earthing?  Surely, a neighbouring wall plate will have its earth connected to every other wall plate in the room by parallel wiring between the plates.

Note: all my cabling is shielded with the shield connected to the earth pin.

128x128lollipopguild

You’ll probably receive a lot of information and advice.

Surely, a neighbouring wall plate will have its earth connected to every other wall plate in the room by parallel wiring between the plates.

I’ll start with this concept first. If you currently have no hum or noise, then you’re lucky.

Your audio system needs to have one common ground that is wired directly to your service panel. These wall receptacles connected together will not have a direct path to ground at the service panel. By plugging your system into this rat’s nest of wiring you are sharing your audio with all the appliances and lighting in your house. This adds noise to the AC line which is audible through your speakers. If these wires have different ground impedances when they meet at the circuit panel, a ground-loop is created. You’ll hear a 60Hz hum thru your speakers if this happens.

 

 

 

 

lollipopguild

Surely, a neighbouring wall plate will have its earth connected to every other wall plate in the room by parallel wiring between the plates.

In the US, it's much more likely that the wiring is done in series, and that's the problem. A dedicated line avoids all those extra connections.

What's important to avoid ground loops is keeping all grounds at the same potential. Plugging everything into one outlet is only one way to achieve that.