Grounding vs Earthing: What's the Difference?

[BSEE]

Every circuits needs to be grounded in order for it to work, but when do we need to take into consideration on earthing it, and what is the difference?

 

[chrisbaird]

"Grounding" is the American English term and "Earthing" is the British English term for the same process: connecting parts of a circuit to an object that acts like an effective infinite drain of charge for the purposes of the given circuit. Note that circuits do not always have to be connected to the physical Earth to be considered grounded, just an object that serves the same purpose.

 

[phinds]

chrisbarid is correct. To add one thing, the term "earth ground" is often used in American English to specify a ground that IS a connection to the earth.

 

[sophiecentaur]

Every circuits needs to be grounded in order for it to work, but when do we need to take into consideration on earthing it, and what is the difference?

I think you are using the wrong term here. A circuit will work perfectly as long as there is a complete path for the current. This is often achieved with just two wires. Which one would you call the 'ground' then? Many systems (vehicles, for instance) use the body as a return path and this can save money for the starter circuit, in particular, as you only need one long thick cable, as the battery negative is usually strapped to the body by a short, thick lead. This is a constant source of problems in old bangers where RUST creeps in and adds nasty series resistance into the circuit so the starter won't turn.