I see some posters mumble about "earthing" vs. "grounding" in the context of lightning protection, and have hard times deciding whether what they say has some sense to it, or is complete balderdash.
I am meaning in the direction of believing that it is complete nonsense.
The term grounding and earthing are one in the same but earthing is the preferred term in British English whereas grounding is the American preference.
Other terms like this are things like flashlight/ torch wrench/spanner etc.
Other times this can lead to some funny things. In British English a "pack of fags" refers to a pack of cigarettes and if you were to "knock up" a girl you hardly knew, that would be just fine in the UK but big trouble in the US.
Electric power systems use "grounding". Grounding has 2 major functions.
One is to provide a low resistance path for a short circuit to reliably trip a breaker. The "neutrals" and "grounds" are connected at services as part of that path. If a failure connects a "hot" to a metal frame, current is carried by ground wires back to the service, then to the source neutral and back to the supply transformer. The earth does not play any significant part in providing this low resistance path.
For the second function, the neutral-ground connection is also connected to earth via water service pipes, ground rods, or several other means. Connecting to earth limits the voltage from earth to frames, conduits, ... and minimizes the voltage from earth to the hot and neutral wires. It also provides a path to dump surges resulting from lightning - the surge follows a path from clouds to the earth. An earth connection is very important particularly in lightning surges.
The second function is sometimes called "earthing" to make clear which "grounding" function is being discussed. If a surge suppressor must be "grounded" it is not terribly clear what is intended. If it is earthed, it is very clear.
The code chapter on grounding may be the most difficult to understand. IMHO one of the reasons is not making the 2 funcitons of grounding clear.
It might help to read the NIST guide on surges and protection:
That "tension" comes from "retension" (meaning 'keeping', for those unable to say what they mean). It's a polite way of saying "Really keep away from those wires. They bite." :-)
That is the UK usage. This newsgroup, at least for electrical, is almost exclusively US-Canada. This side of the pond "earthing" is not common usage but refers to a connection to earth.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.