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.



starred earth (ground)

Think of your circuit breaker box as home base, and a single point. Each individual circuit in your house (apartment, condo or office building), or run of AC wiring, ends up terminating in this load center. This is also where all of the grounds (including your ground rods and utility pipe grounds - water/gas pipe) to these circuits terminate. If you saw this single point in your circuit breaker box (even though it’s a bus bar), with all of these grounds attached, it would kind of look like a star. Hence the reference.

Star grounding can also relate to audio gear AC power connections. If the gear has 3 prong plugs, when plugging them all into a wall outlet, or power strip, the 3rd prong is the earth ground. You want only one ground connection per piece of audio equipment, hopefully on the same circuit, unless you have separate circuits with dedicated isolated grounds. Connecting audio gear together which is on different circuits can create ground loops, since the grounds on other circuits may be at a different ground potential. In that case, if you’re connecting via balanced XLR connections, it’s important to pay attention to pin 1 of the XLR connection. In that case, to prevent a ground loop, pin 1 should be lifted on one end of the cable.


A star ground is a pattern of 3 or more grounding rods all connected together and connected to the earth ground terminal in a power distribution box.

Having dealt with lightning strikes to radio broadcast towers on an annual basis for many decades, and electricians installing ground systems to divert these strikes, the better choice is to connect all ground rods together (not as individual runs to the single point of reference), with *one* connection to the single point of reference. You can also form a loop of ground rods around a building, with both loop ends tied to the single star point.

Hi @dpop - many thanks for your explanation, and the time you put into it.

It certain beats the following DM I received from @riley804 


do you have google ?

if you google your title, you will find your info that you are looking for.



Are you being sarcastic? If you are, please have the balls to be public about it on the thread.



maybe if you weren’t so lazy, you could have looked this up yourself and learned something


better ?

@riley804 Asking advice on earthing and powering an amplifier is surely the whole point of a forum.  If such a request upsets you so much, best not to scan forums.

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