General Order 95
Requirements for All Lines
39 Minimum Clearances of Wires from Signs
Clearance between any overhead line conductor and all signs, whether mounted on buildings, isolated structures or otherwise constructed shall not be less than the values given in Table 2–A at a temperature of 60 °F. and no wind.
The clearances specified in Table 2–A shall in no case be reduced more than 10% because of temperature and loading as specified in Rule 43 . All clearances of more than 5 inches shall be applicable from the centerlines of conductors concerned. Lesser clearances shall be applicable from conductor surfaces.