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Subject - isolated ground receptacle circuits
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phughes
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 Can someone please tell me if you need a separate ground bar in the panel for isolated ground receptacles grounding conductors to connect to to be effective? If so,should this separate ground bar be isolated or insulated from the panel enclosure?
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Ryan_J
| Yes, they should be isolated...hence the name.
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blackrd
| I just read an article(that I dont have with me), and it was on this topic. Where you need an isolated ground outlet because of transient interference (or something like that)where you run an additional grounding wire soley for the receptacle whose grounding is isolated from that of the j-box and raceway that supplies it. The article went on to say that if your feed conductors for the receptacle makes several passes through multiple panelboards to get to the receptacle, that the grounding wire for the receptacle only had to go back to the panelboard nearest the receptacle. My understanding of the article was that the isolated recep was isolated at the recep by an additional grounding wire seperate from the grounding to and of the raceway(if the raceway were to apply. The article didnt state anything about isolation or insulation from the panel enclosure. Am iI correct in my interpretation of an isolated ground receptacle? Or am I incorrect?
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Electricman
| Isolated grounding conductors are terminated at the main service panel on a seperate buss, but since it is the main point of disconnect the neutral buss is still bonded. Note that the use of an isolated grounding conductor does not relieve the requirement for grounding the raceway, it is usually used where electromagnetic interference is an issue. Read 250.96 (B) & 146(D). It is interesting that the code is silent as to whom decides whether an isolated ground is required or not.
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blackrd
| Im going to find that article and reread it.
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