Deenergizing Lines & Equipment

 

Before starting work on power transmission/distribution systems, crews must determine existing conditions by inspection or test. One critical condition that must be determined is whether lines and equipment are energized or deenergized.

Deenergizing lines and equipment

When deenergizing lines/equipment operated in excess of 600 volts, and the means of disconnecting from electric energy is not visibly open or visibly locked out, the following rules apply:

·               The particular section of line or equipment to be deenergized must be clearly identified, and it must be isolated from all sources of voltage.

·               Notification and assurance from a designated employee must be obtained that:

-        All switches/disconnectors through which electrical energy may be supplied to the particular section of line or equipment to be worked on have been deenergized.

-        All switches/disconnectors are plainly tagged indicating that employees are at work.

-        Where the design of the switches and disconnectors permits, they have been rendered inoperable.

·               After all designated switches and disconnectors have been opened, rendered inoperable, and tagged, visual inspection or tests must be conducted to ensure that equipment or lines have been deenergized.

·               Protective grounds must be applied on the disconnected lines/equipment to be worked on.

·               Guards or barriers must be erected as necessary to adjacent energized lines.

·               When more than one independent crew requires the same line or equipment to be deenergized, a prominent tag for each crew must be placed on the line or equipment by the designated employee in charge.

·               When completed with work on deenergized lines or equipment, designated employees in charge must determine that all employees in their crew are clear, that protective grounds installed by their crew have been removed, and they report to the designated authority that all tags protecting their crew may be removed.

When a crew working on a line or equipment can clearly see that the means of disconnecting from electric energy are visibly open or visibly locked-out, the following provisions will apply:

·               Guards or barriers must be erected as necessary to adjacent lines.

·               Upon completion of work on deenergized lines or equipment, each designated employee in charge must determine that all employees in their crew are clear, that protective grounds installed by their crew have been removed, and they must report to the designated authority that all tags protecting their crew may be removed.