Equipment Grounding Conductors for Parallel Runs

Michael Johnston

Many commercial and industrial electrical designs incorporate larger feeders or branch circuits to supply equipment; these high capacity circuits necessitate the use of parallel conductor arrangements. Installing parallel conductors becomes a necessity when larger circuit conductors are required for supplying switchboards and other large electrical equipment, simply because very large single conductors are not practical, economical, or even available in many cases. Installing feeders or circuits in parallel requires compliance with 310.4, which means the conductors must be the same length, material, and size; must have the same insulation; and must be terminated in the same manner. Installing conductors in parallel for feeders means that multiple conductors are electrically connected at both ends to create a single conductive path or conductor. Where the entire parallel arrangement of conductors is installed in a single raceway, cable, or cable tray, a single equipment grounding conductor (EGC) is permitted to be installed.