Here is Pennslyvania law on the subject: “Signs on Utility Poles Posting signs on utility poles is illegal and unsafe. This includes signs advertising businesses, products or services as well as ‘For Sale’ or ‘For Rent’ and election signs and signs for yard sales or festivals. Pennsylvania law prohibits the use of any metal or hard substances such as nails, tacks, staples or metal fasteners for attachments to utility poles unless these attachments have been reviewed by engineering and an attachment agreement prepared and signed by all parties involved. A person is guilty of a summary offense if he drives a nail or hard substance to or into any pole of any public utility pole line. Exceptions does not apply to: (1) the public utility or its licensee using the poles from affixing its metal or other markers or from otherwise using the poles in its public service or (2) the erecting traffic signs and other signs similar thereto by a municipality when authorized by statute or by the owner of such poles.”