yes, issues with multiple sources of ground and ground potential. Also UL Standard 2200, Section 18.1.6 requires that a terminal for the connection of a grounding electrode conductor must be provided on any UL listed generator. In the past, Generac provided a lug on the outside of the enclosure to serve this purpose. In 2014, Generac redesigned the connection shelf in the air-cooled generator. The redesign now allows for the connection of a grounding electrode conductor and the system bonding jumper between the equipment ground bar and neutral terminal bar. By permitting these terminals to be installed inside of the generator enclosure, UL allows the removal of the grounding electrode lug on the outside of the enclosure.
Generac optional standby system generators are, by design, floating neutral generators, and are designed to be installed with a transfer switch that has a solid neutral connection to the premises-supplied electrical service and grounding electrode system. This is referred to as a nonseparately derived system. (Refer to Informational Note No. 1 in 250.30 in the NEC.) The equipment grounding conductor that is part of the feeder conductors from the generator to the transfer equipment will ground and bond all of the non-current carrying metal parts of the generator to the grounding electrode system at the electrical service.
Only when the transfer equipment contains a switching action for the grounded (neutral) conductor will a grounding electrode system and system bonding jumper be required to be installed on the generator. This is the definition of a separately derived system, because the generator does not have a direct electrical connection to the premises- supplied electrical service.
