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Thursday, September 17, 1998
Question:
An inspector observes the service drop crossing the roof overhang to a through the roof raceway. After measuring the drop (3 1/2 feet from the edge to the conduit, and 5 1/2 feet along the edge from the point of the drop crossing to even with the conduit), he writes you up for to much of the drop crossing the roof. Was he right? How much of the drop crosses the roof?
A
Answer:
Yes ... well ... sort of ... the inspector was correct if the service drop was installed by a contractor instead of the electric utility, see 230-24(a) Exception No. 3. A little over 6 1/2' hangs over the roof. 3.5 squared plus 5.5 squared = 42.5, then take the square root of 42.5.
If the electric utility installed the service drop, then National Electrical Safety Code rule 234C3d(1) Exception 2 would apply. This rule makes a statement the same as the National Electrical Code; however, after a radial distance of 6 feet from the through the roof raceway termination is met, the National Electrical Safety Code will permit the service drop to continue across the roof as long as a vertical clearance of three feet is maintained. Furthermore, there is no mention in the National Electrical Safety Code about the slope of the roof, only that it is not to be readily accessible.