25 Pa. Stat. § 2648
The records of each county board of elections, general and duplicate returns, tally papers, affidavits of voters and others, nomination petitions, certificates and papers, other petitions, appeals, witness lists, accounts, contracts, reports and other documents and records in its custody, except the contents of ballot boxes and voting machines and records of assisted voters, shall be open to public inspection, except as herein provided, and may be inspected and copied by any qualified elector of the county during ordinary business hours, at any time when they are not necessarily being used by the board, or its employes having duties to perform thereto: Provided, however, That such public inspection thereof shall only be in the presence of a member or authorized employe of the county board, and shall be subject to proper regulation for safekeeping of the records and documents, and subject to the further provisions of this act: And provided further, That general and duplicate returns, tally papers, affidavits of voters and others, and all other papers required to be returned by the election officers to the county board sealed, shall be open to public inspection only after the county board shall, in the course of the computation and canvassing of the returns, have broken such seals and finished, for the time, their use of said papers in connection with such computation and canvassing.
25 P.S.§ 2648