Pennfield Corporation (plaintiff) owned a pig farm in Pennsylvania. Meadow Valley Electric, Inc. (MVE) (defendant) repaired and maintained the electrically operated ventilation system for the pigs’ enclosure. The ventilation system malfunctioned, causing 1,537 pigs to asphyxiate. Pennfield sued MVE, alleging that MVE installed a defective electrical system that caused the enclosure’s ventilation system to fail and suffocated the swine. MVE filed a complaint to join, among other defendants, York Electrical Supply Co. (York) and Tri-State Electrical Supply Company (Tri-State). MVE alleged that the ventilation system’s failure was caused by defective electrical cable negligently supplied by either York or Tri-State. MVE further alleged that the electrical cables it purchased from York and Tri-State were indistinguishable. York objected to joinder, arguing that MVE could not make out a case for negligence without identifying which defendant had supplied the defective electrical cable. The trial court sustained York’s objections, dismissing MVE’s complaint against York. MVE appealed.