Update on outbuilding grounding requirements

This isn’t really a question, rather a correction to something I posted earlier. The main building with the primary service requires it’s own grounding system (of course) with the neutral bonded to the ground. Sub-panels in the same building require the neutral isolated and a separate ground wire for the grounding bussbar (a 4 wire feed, assuming 240v) back to the main panel. An outbuilding panel fed from the primary service panel again requires the neutral to be isolated from the ground AND the outbuilding have it’s own grounding system AND requires a 4 wire service. Others here in Washington state have told me that the outbuildings should NOT have their own grounding system and I have found that’s incorrect. So with the help from others here, consultation with the electrical inspector, I now believe we are in sync with the rest of the country. Sorry for any confusion I may have caused. I’ll try and find the original posts and edit them based on what I now know.