Parallel conductor installations are covered in NEC ® 310. 10 (H) and are permitted for each phase, polarity, neutral, or grounded conductor in sizes 1/0 AWG and larger. Joining conductors in parallel is like having two or more smaller conductors connected at each end to make one. Wiring diagram shows both PNP and NPN wiring. Actual units use PNP status indicator, NPN status indicator, or neither. 81 ft)]. In the 2017 NEC, parallel conductors inside an auxiliary gutter must be grouped together to prevent current imbalance in the paralleled conductors due to inductive reactance. Parallel. Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Check for proper IP/NEMA ratings and material quality. Ensure safe placement: install in dry, accessible areas with good ventilation and at appropriate height (typically ~1. Author's Comment: When conductors are installed in parallel (electrically joined at. The installation requirements and specifications of Distribution box involve many aspects, including site selection, fixing method, wiring specifications and safety protection. This code is based upon the type of box, wires, wire sizes, wire clamps and conduit fittings.