sparky66wv,
1. Separate systems in the same facility are
required to be grounded to the same grounding electrode, or, the grounding electrodes are required to be interconnected.
2. The reason that the transfer switch in Diagram 2 is required to switch the neutral is to prevent the neutral being in parallel with the equipment grounding path (green),
when the generator neutral is bonded to the frame, which would create the problem shown in Diagram 3 (above).
3. When the transfer switch breaks the neutral, as in Diagram 2, we have, in effect,
two separate systems, only one of which is active at any time.4. Look at each system individually.
a. Load on utility power (Diagram 4 – this post). Unbalanced load current flows from the load neutral bus (X) back
to the source it came from (Z). ![[Linked Image from electric-ed.com]](http://www.electric-ed.com/images/Gen7.gif)
b. Load on generator power (Diagram 5 – this post). Unbalanced load current flows from the load neutral bus (X) back to the source it came from (Y).
![[Linked Image from electric-ed.com]](http://www.electric-ed.com/images/Gen6.gif)
Ed
[This message has been edited by electric-ed (edited 11-23-2002).]
