My journeyman installed 3 duplex receptacles in 3 separate 1900 boxes. 1 of the receptacles was grounded in the common fashion, and 2 of the receptacles had to have an isolated ground. All 3 were linked together by EMT. So what we did was pull a common ground and bond all the boxes and 1 receptacle with it. And we pulled a separate ground and grounded ONLY the 2 receptacles that required an isolated ground. Hope this helps...not sure if applicable.
