Dedicated line -Ground wire, what size did you use

I am not familiar with Malaysian electrical codes, but electricity is electricity regardless of where in the World you are, and behaves in the same way. At 150 feet from the meter box, instead of running multiple branch circuits, you could have run a single large feeder to a subpanel in your dedicated room, and from there, run individual circuits.

The earth is not a sponge to absorb electricity, it has a relatively high impedance. If you have a ground fault (short circuit) in the wiring or connected equipment that energizes metallic surfaces, the fault current will look for the easiest route back to its source, the power company transformer.

When you have a separate rod as the grounding means, the earth's impedance is not low enough to pass the amount of current that will cause the circuit breaker to trip and the ground fault will remain, posing a continuing shock hazard.

When a circuit is properly grounded at the main electrical panel/meter box, any ground fault current will flow back to the power company transformer at high amperage, because there is a direct connection between the two (low-impedance path), cause the circuit breaker to trip, and eliminate the shock hazard. Grounding at the main electrical panel/meter box is primarily to stabilize the electrical supply voltage. The power company transformer is also grounded at the pole.

Now, regarding lightning. When you connect your system to a separate ground rod that is not bonded to the main grounding electrode, any lightning strike that occurs between the two grounds, will cause lightning current to flow in the circuit because of the difference in impedance between the two grounds. Connecting the two grounds solves that problem because they will be at the same impedance (zero).

It is a common audiophile misconception that the earth is some sort of noise absorber and that a separate ground rod is the appropriate cure.

See the following link to a drawing I created that will hopefully show the relationship between the electrical source, your wiring/equipment, and ground fault current.

http://img.villagephotos.com/p/2003-5/191557/Ground%20Fault.JPG

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Thank you for the detail explanation and drawing and it seems so logical. Looks like a lot of us with dedicated room is doing it the wrong way for the sake of better quality sound at the expense of endangering our life. Wonder why my electrician did the grounding for my dedicated room in this manner. Thanks

Gbart

Clarification:Malaysia electrical codes.
The power company incoming wires is only live and neutral wires and developer provide the grounding electrode. Thanks

I did some resarch on the Malaysian electrical system. It is the same as United Kingdom. North America also has incoming live and neutral from the power company, and the electrician installs the grounding electrode. The same grounding rules apply in both cases. The power company transformer (the power source) is grounded at its location.

For circuit breakers to trip when there is a ground fault, the current has to be able to get back to the source (i.e, the power company transformer) at a rate that is high enough to cause the breaker to trip. The resistance of the earth is too high to accomplish this. The breaker will just "see" the ground fault current as a normal (high resistance) load and not trip. That is why any supplementary ground rods must be bonded to the main grounding electrode (which is also connected to the incoming neutral, which is also grounded at the source (transformer). I'm glad that you understood what I was trying to say.