Exhibit 23 CONSENT OF INDEPENDENT ACCOUNTANTS We consent to incorporation by reference in the Registration Statement on Form S-8 (File No. 333-45949) of Pennsylvania Manufacturers Corporation of our report dated February 6, 1998, appearing on page 88 of the Annual Report to Shareholders which is incorporated in this Annual Report on Form 10-K. We also consent to the incorporation by reference of our report on the Financial Statement Schedules which appears on page S-9 of this Form 10-K. /s/ Coopers & Lybrand L.L.P. One South Market Square Harrisburg, Pennsylvania March 15, 1998