Earth

[Tom749]

What is the main differences among earth, pole earth, line earth, frame earth? Thanks for your help in advance. Edited September 7, 2011 by Tom749

[Shiner]

Earth ground is a ground derived from an individual source, (rod, ring, ect) a pole ground is derived from the ground of the transmission system and can be noisy from line transients, frame ground is a common using the steel of an enclosure or system used to tie all signal grounds together and usually having a separate ground tied to the earth ground (this way transients on the system become common and will not be as noticeable on the signal) but can also be floating, and line ground is referred to here as a high leg or corner grounded delta system and depending on the strength of the resistance to ground, potentially dangerous. There are only a few places in my area that have this last type of system still in use. I have seen frame grounds in controls, where niether side of the load of the control transformer is grounded, and the system has two ground detection lights. The idea is if a wire shorts, one of the lights will light letting you know that you have a fault. Without this if you were to have a fault on the Nuetral (grounded) side of the control, current would pass through the frame of the machine or enclosure undetected(until someone provides a better path to ground). This too is becoming less common as breakers with ground fault detection come into use more and more. What is it you are trying to determine?