Ground-fault circuit interrupter (GFCI) protection for personnel or a similar protection technique has been in the National Electrical Code (NEC) since 1962 with specific reference to GFCI and its definition found in the 1968 NEC.
Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Questions can be sent to firstname.lastname@example.org. Answers are based on the 2014 NEC. Pull boxes for communications cable