smalltime
Member
- Location
- Roanoke, VA
640.3 defines a Technical Power System as:
"An electrical distribution system with grounding in accordance with 250.146(D), where the equipment grounding conductor is isolated from the premises grounded conductor except at a single grounded termination point within a branch-circuit panelboard, at the originating (main breaker) branch-circuit panelboard, or at the premises grounding electrode."
So it's an IG system. But what I'm struggling with is that it says, "...where the equipment grounding conductor is isolated from the premises grounded conductor..." Wait a minute. The regular EGC is insulated from the grounded conductor (neutral) until the single termination point. What's the difference?
Shouldn't it say, "...where the equipment grounding conductor is isolated from the premises grounding conductor..." In other words the IG grounding conductor is isolated (insulated) from the EGC until a single grounded termination point.
What am I missing?
"An electrical distribution system with grounding in accordance with 250.146(D), where the equipment grounding conductor is isolated from the premises grounded conductor except at a single grounded termination point within a branch-circuit panelboard, at the originating (main breaker) branch-circuit panelboard, or at the premises grounding electrode."
So it's an IG system. But what I'm struggling with is that it says, "...where the equipment grounding conductor is isolated from the premises grounded conductor..." Wait a minute. The regular EGC is insulated from the grounded conductor (neutral) until the single termination point. What's the difference?
Shouldn't it say, "...where the equipment grounding conductor is isolated from the premises grounding conductor..." In other words the IG grounding conductor is isolated (insulated) from the EGC until a single grounded termination point.
What am I missing?