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Q. Can flexible metal conduit or surface metal raceways be used for branch circuits in patient care areas where wiring must be provided with a ground path for fault current?
A. Flexible metal conduit in lengths not exceeding 6 ft can be used for branch circuit wiring in patient care areas of a health care facility if the circuit conductors contained in the raceway are protected by overcurrent devices rated at 20A or less. A redundant equipment grounding conductor is also necessary. In addition, 250.118(6)c points out that where the flexible metal conduit is part of the ground return path, the total combined length of the flexible metal conduit in that run cannot exceed 6 ft.
Surface metal raceways are also considered suitable for grounding unless they have some marking – like UL information – that would prohibit its use as a sole grounding path.