I think the Hondas are the inverter type, so they sync easier. But I think the op is meaning two separate transfer switches along with two separate sub panels.
well, what he said....
"Maybe I didn't make myself clear. The customer wants 2 Portables
Genns with 2 transfer switches from the same service. (same panelboard)
Have you ever seen this set up before?"
sounds like the man wants to feed a common bus...
the slick thing to do would be to have a transfer switch that
would pull in the second genset when needed, sync, them, and shed it
when not needed..... i've not seen anything that cool for a residential application.
when they tie big generators to the grid in powerhouses, they match them
within a degree or so, iirc. before closing.... once they are closed, the
electrical coupling is as strong as a driveshaft, and if one can't keep up, it relays out.