NEC Standards of Safety
Publisher Summary Many people think of NEC requirements as a performance standard, when they actually provide the bare minimum for safe installations. The guidelines are not meant to provide the most convenient or efficient installations and don't even guarantee good service or allow for future expansion. They are designed to provide a standard for safety that protects against electrical shock and thermal effects, as well as dangerous overcurrents, fault currents, and overvoltage. The insulation on a conductor imprisons the dangerous electrical current running through it and guards against shock, fire, and arc incidents. For this reason, one must size conductors properly so that excessive loads do no overheat the conductors and damage the protective insulation. Article 310 of the NEC deals with the minimum size requirements for conductors based on their voltage rating. NEC Article 310.15 addresses ampacity, which needs to be cross-referenced to NEC Table 310.5, because Article 310.15 doesn't take voltage drop into consideration.