OK here goes
Wigglyamps, an aircraft wiring system is basically simililar to a car,live to the equipment, neutral (also called earth) return usually by the frame.
(as DFC said)
Garage Years
Your quote is only valid in the country to which it applies - USA
Wigglyamps is UK based and the regulations/systems & legislation are totally different. With building wiring coming under the Institution of Electrical Engineers 17th edition wiring regulations. Public supply networks under the Electricity,Safety, Quality & Continuity Regulations 2002.
Similarly Lightning protection systems are totally sepereate and are never connected to any point of a wiring system
DFC
Since you will understand the theory here is a brief synopsis which while not 100% technocally correct will give you an idea of the difference;
Domestic - We will start on the distribution network at the transformer - star 3 phase system with centre earth. Each phase will have the same potential to earth and at this point the centre is connected to earth.
From here two "wires" go to your house - Phase (live) and another "wire" which is connected to the centre point (Neutral).
Therefore at the transformer, the resistance of the neutral wire to earth is very low but as one moves farther from the transformer, the resistance of the neutral wire causes the resistance back to earth via the centre point to increase.
Let's now think of your house. It will most likely these days have a earth conductor which utilises an earth rod close to the property. The earth wires are of minimum sizes and this combined with the shorter distance top earth via the earth wire compared to the neutral.
Therefore given the choice, current will flow via the earth wire and not via the neutral. This is used to trip the ELCB.
Connecting metal enclosures to earth ensures that any fault current caused is suficient to trip a CB within the desired maximum time.
Bonding all pipework etc and earthing them ensures that you don't end up with possible voltage differences.
At the transformer the neutral is connected to the centre point, this is also connected to earth.
(at this point the resistance to the general mass of earth is below 1ohm in urban networks and 20ohm in rural networks)
In older systems a seperate earth is part of ALL cables and is often connected to the house earthing bonding/wires
In modern systems the neutral and earth run combined upto the customers property where they are then split and presented as seperate terminals
The majority of houses in the UK have a seperate earth terminal connected to the supply network. A seperate earth rod is only seen in rural areas and even then not very often.
An ELCB well a modern Residual Current type operates by monitoring the difference between the current in the live & neutral, if they differ by more than the setting of the device e.g. 30mA it will operate
You are correct with the bonding of all metal work, the theory being to ensure during a fault that everything should be at the same potential
The other reason in the UK to bond the centre point of a 3 phase transformer to earth is to maintain the neutral at electrically zero potential. Loss of this bond, can due to unbalanced loads, allow the neutral to electrically float leading to excess volts being delivered to customer's premises - with serious results.