NFPA 70 NEC has added an alternative classification system based on Zones, similar to the IEC system. (It’s important to note that in the U.S., the Zone system is more prevalent in the chemical and petrochemica
In the U.S., local codes have almost entirely adopted NFPA 70 standard as theNational Electrical Code(NEC) in full, or based their own requirements on it. The NEC lays out required practices for all aspects of residential and commercial electrical installation. Every three...