Without re-reading the entire thread, I can't remember if this has been discussed.
Consider this scenario:
- Generator is not provided with a ground rod
- Equipment with a grounding conductor is powered by the generator
- Other equipment with a grounding conductor is powered by installed circuits ("shore power")
- The variously-powered equipment is connected by an audio interconnect with a shield that's connected at both ends
At this point, the shield of the audio interconnect becomes the sole connection between the ground of the generator circuit and the ground of the shore power.
What is the implication? Does this pose a potential threat to either personnel or equipment? What kind of fault could cause excessive current flow through the shield resulting in melting or fire? What kind of fault could cause electric shock?
It seems to me -- and I have not studied this in an engineering fashion -- that where there is potential to power interconnected equipment from disparate sources, it would be wise to connect the grounds of those sources in some fashion. However, I would be concerned that connecting those grounds could result in large ground currents in the cross tie.