Medium and high-voltage installations Low-Voltage Electrical Service(Blue Book)		Low-Voltage Electrical Service: Standard E.21-10 (9th edition) This standard sets out the conditions for low-voltage electricity service. More specifically, it deals with permanent and temporary connections to the overhead or underground distribution system and metering of low-voltage supply. It is designed to provide Hydro-Québec employees, master electricians, consulting engineers and manufacturers with information on implementing or modifying electrical installations. Complete document [PDF—3.92 KB] Approved Products [PDF—494 KB]