euipotential bonding - other advantages

[rumplestiltskin]

A far as I am aware EB is designed to bring anything connected to it up to close to the supply voltage during a fault condition. EG - during the fault and the allowable (up to) 5 seconds for a fuse to blow the EB might come up to 180v, so with 230/240 in one hand and 200 in the other you will live to rewire the fuse. If I've got that wrong let me know.
There are two other advatages of it I can think of;
It introduces a parallel earth path and lowers Ze.
If the main earth is damaged or lost it will perform as a substitute.

Can anyone think of any other advantages of disadvantages?

 

[Spark123]

One of the main purposes of equipotential bonding is to limit the touch voltage between exposed/extraneous conductive parts to 50v in the event of a fault, if this voltage is to be exceeded then automatic disconnection should occur within the specified time limit.

 

[rumplestiltskin]

I'm not too sure if you are saying the same thing as me in a different way or suggesting something subtly similar or different?
An extraneous conductive part is not part of the electrical installation and is liable to introduce earth potential, and should be equipotentially bonded.
An exposed conductive part is part of the electrical equipment (or connected to it) which could become become "live" under fault conditions, and should normally be connected to the CPC, or some other means of connection to the MET, to cause automatic disconnection.

 

[Spark123]

Yep, the MET is basically your reference for all exposed/extraneous conductive metalwork within the premises.
The purpose of equipotential bonding is to keep the exposed/extraneious conductive parts at the same potential throughout the equipotential zone.
The main ways for a potential to exist on an exposed/extraneous part is by it being introduced from outside or by a fault.
If these are both dealt with by means of equipotential bonding and automatic disconnection of supply then a large potential either cannot exist or cannot exist for long enough to cause danger.
In a Terre system these will be referenced to earth, hence EEBADS.