Mains sockets and star earth - can anyone explain?

lollipopguild12

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.

@lollipopguild 

You might find some interesting reading material here on the subject:

Power Distribution and Grounding for Audio, Video

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. This is usually a more effective ground compared to a single point ground which is common in housing in the US. You should be able to find plenty of information on grounding methods on the net or check out the book "Grounds for Grounding" or find out what the traditional phone companies used in your area.

Unless you have dedicated wiring for your stereo it has short comings, ground loops are just one of the possible issues. Voltage drop is probably a more common issue, wiring is probably to small creating a weak link in the performance.

@lollipopguild

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.

@audio-union

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.