Working On or Near Energized Circuits
Live parts to which an employee may be exposed must be de-energized before the employee works on or near them unless de-energizing the parts introduces additional or increased hazards or is unfeasible due to equipment design or operational limitations. Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area. Live parts that operate at less than 50 volts to ground need not be de-energized if there are no increased exposures to electrical burns or to explosions due to electric arcs.
De-energized Parts
When employees work on de-energized parts or near enough to them to expose the employees to any electrical hazard they present, the following safety related work practices must be followed:
- Treat as energized any conductors and parts of electrical equipment that have been de-energized, but have not been properly locked out or tagged.
- While any employee is exposed to contact with parts of fixed electric equipment or circuits which have been de-energized, the circuits energizing the parts shall be locked out or tagged or both. In addition, electrical hazards must be controlled; a qualified person must test the circuit to verify deenergization from all voltage sources.
- Safe procedures for de-energizing circuits and equipment must be determined before circuits or equipment are de-energized. All electric energy sources must be disconnected. Control circuit devices, such as push buttons, electric switches, and interlocks must not be used as the sole means of de-energizing circuits or equipment. Interlocks must not be used as a substitute for lockout and tagging procedures.
Energized Parts
Employees are considered working on or near exposed energized parts when working on exposed live parts either by direct contact or contact be means of tools or materials or when working near enough to energized parts to be exposed to any hazard they present. Only qualified persons are permitted to work on electric circuit parts or equipment that have not been de-energized (lockout/tag out). Qualified persons are capable of working safely on energized circuits and are familiar with the proper use of special precautionary techniques, personal protective equipment, insulating and shielding materials, and insulated tools.
| Approach distances for qualified person to alternating current | |
|---|---|
| Voltage Range (Phase to Phase) | Minimum Approach Distance |
| 300V and less | Avoid contact |
| Over 300V, not over 750V | 1 foot |
| Over 750V, not over 2kV | 1 ft. 6 in. |
| Over 2kV, not over 15kV | 2 feet |
| Over 15kV, not over 37kV | 3 feet |
| Over 37kV, not over 87.5kV | 3 ft. 6 in. |
| Over 87.5kV, not over 121kV | 4 feet |
Overhead Lines
When work is to be performed near overhead lines, the lines must be de-energized and grounded, or other protective measures taken before the work is started. Such protective measures, such as guarding, isolating or insulating, shall prevent the qualified person performing the work from contacting the lines with any part of their body or indirectly through conductive material, tools, or equipment.
Unqualified persons working in an elevated location near overhead lines are not allowed to come closer or to handle the conductive objects which may contact or come closer to any unguarded, energized overhead line than the following distances:
| Voltage to Ground | Distance |
|---|---|
| 50kV or below | 10 feet |
| Over 50kV | 10 feet (plus 4 in. for each 10kV over 50kV) |
Unqualified persons working on the ground in the vicinity of overhead lines are not allowed to bring a conductive object or any insulated object which does not have the proper insulating rating closer to unguarded, energized overhead lines that the distance specified above.
Qualified persons working in the vicinity of overhead lines, whether in an elevated position or on the ground, are not allowed to approach or take any conductive object without an approved insulating handle closer to exposed energized parts that in the table above, Approach Distance for Qualified Persons, unless a.) The person is insulated from the energized part by using the proper gloves, with sleeves if necessary, rated for the voltage involved, or b.) The energized part is wholly insulated from the person, or c.) The person is insulated from all conductive objects at the potential different from the energized part.