California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 5 - Electrical Safety Orders
Group 2 - High-Voltage Electrical Safety Orders
Article 36 - Work Procedures and Operating Procedures
Section 2940.19 - Series Streetlighting

(a) If the open circuit voltage exceeds 600 volts, the employer shall ensure that employees work on series street lighting circuits in accordance with Sections 2940.7, 2941, 2943, 2946 and 2940.15 of these Orders, as appropriate.

(b) Before any employee opens a series loop, the employer shall deenergize the street lighting transformer and isolate it.