Many older remote building feeders have been installed using 3 conductors without a ges at the remote building. No continuous metal exist between buildings. Just direct burial or pvc between the buildings. I usually get to inspect the installation after a lightning event.
A grounding path to a ges is needed so a ground rod and an egc can be installed.
Now the grounded and grounding conductors need to be separated to an isolated neutral bar and a grounding bar.
Then a single ges is required to avoid potential difference between the remote building ges and the service ges, so...
(1) Does adding the grounding conductor to the feeder circuit to the remote building provide bonding of the remote building ges to the service building ges thus forming a single ges?
(2) Does a bonding conductor between a remote building ges and the service building ges allow a 3 conductor feeder circuit with only a feeder neutral?
(3) Is a bonding conductor connecting the remote ges and the service ges required "and, also" a fourth feeder conductor for the circuit grounding conductor?
I have read both the NEC 2005 and 2008 concerning this issue and find it very difficult to answer those 3 questions...
A grounding path to a ges is needed so a ground rod and an egc can be installed.
Now the grounded and grounding conductors need to be separated to an isolated neutral bar and a grounding bar.
Then a single ges is required to avoid potential difference between the remote building ges and the service ges, so...
(1) Does adding the grounding conductor to the feeder circuit to the remote building provide bonding of the remote building ges to the service building ges thus forming a single ges?
(2) Does a bonding conductor between a remote building ges and the service building ges allow a 3 conductor feeder circuit with only a feeder neutral?
(3) Is a bonding conductor connecting the remote ges and the service ges required "and, also" a fourth feeder conductor for the circuit grounding conductor?
I have read both the NEC 2005 and 2008 concerning this issue and find it very difficult to answer those 3 questions...