Generator Grounding\
REF: Soares Book of Grounding, page 146

Separately Derived Systems

Figure 12-8 illustrates a separately derived system from a generator. Note that there is no connection, including that of a solidly grounded neutral, between the two systems. An easy way to determine whether or not the generator is a separately derived system is to examine the transfer switch. If the neutral and all phase conductors are switched, it is a separately derived system. If the neutral is not switched, but solidly connected, then it is not a separately derived system.

Where the generator is a separately derived system, the neutral bonding jumper must be installed, either at the generator or at the first disconnecting means or over-current device or any point between. In addition, a grounding electrode conductor must be installed between the neutral and a grounding electrode.

Generator not separately derived

Where the generator is not a separately derived system, the neutral bonding jumper must be removed from the generator, and the neutral must not be grounded at the generator or at any point between the generator up to the service.

In this case, the system is grounded by its solid connection to the neutral of the premises wiring system. An equipment grounding conductor is installed throughout the system with the circuit conductors between the service, transfer switch, and other non-current carrying parts of the installation.

Additional information and site survey information can be obtained by contacting

POC: Mike Helms mike@lightningmike.com