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Tuesday, November 8, 2016
Question:
Charlie,
I never heard of a pergola, but a picture is attached. The question is, is the top considered a roof, and what clearances are required to the overhead service conductors? In this particular case, the service drop is about 1 foot higher than the "roof" and just a few inches to the side of the structure.
Thanks for your advice.
Dave Rutkowski
A
Answer:
Hey Dave thanks for your question. The terms "pergola" and "roof" are not defined in the NEC so we can use standard dictionary definitions. One abbreviated definition of pergola is a garden structure of vertical posts or pillars that usually support cross-beams and a sturdy open lattice. A roof can be defined as an upper covering of a building. I would not consider the upper portion of an open pergola to be a roof.
Overhead service conductors must not be located so they are readily accessible (as defined in Article 100) and must comply with the clearances in 230.24. There are some exceptions in that section but they would not likely apply to a pergola. Keep in mind that the clearances from grade need to be 10 feet as stated in 230.24(B) under the described conditions.
You use the term "service drop" which is for conductors owned by the utility as defined in Article 100 so you might consider asking if they have rules that apply to clearances from or over structures.