ground rings - 07/08/03 10:26 PM
250.52A4 says "A ground ring encircling the building or structure, in direct contact with the earth, consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 2 AWG."
Circle: Ellipse in which the two axes are of equal length; a plane curve generated by one point moving at a constant distance from a fixed point.
Encircle: Form a circle around.
so... not many circular buildings... we can assume that we probably don't need to form a perfect circle around the building, but do you assume that going completely around the builidng is required? some guys tell me that it doesn't really mean what it says about encirlcing the building, just use at least 20 feet of 2awg Cu... but how is that as good as a ufer since that is ok as an alternative? so i don't buy that... but then again, if you calculate a 20 foot circumference around a building, then it would probably be a dog house.
so my question is.... what does the NEC intend for us to do if we decide to use a ground ring? entirely encircle the building? go 20 feet along one side of the building?
Circle: Ellipse in which the two axes are of equal length; a plane curve generated by one point moving at a constant distance from a fixed point.
Encircle: Form a circle around.
so... not many circular buildings... we can assume that we probably don't need to form a perfect circle around the building, but do you assume that going completely around the builidng is required? some guys tell me that it doesn't really mean what it says about encirlcing the building, just use at least 20 feet of 2awg Cu... but how is that as good as a ufer since that is ok as an alternative? so i don't buy that... but then again, if you calculate a 20 foot circumference around a building, then it would probably be a dog house.
so my question is.... what does the NEC intend for us to do if we decide to use a ground ring? entirely encircle the building? go 20 feet along one side of the building?