Electrical system

Many electrical lines, circuits, and systems are worked on while energized. This is often because the system loading or its configuration, or both, makes it impossible to deenergize the system, or because continuity of customer service must be maintained. However, some work can only be done with the system deenergized, such as splicing underground cable or work inside a boiler. Most electric work can be done safely while energized using special techniques and equipment that have been developed over the years.

Merely opening a switch or closing a valve does not satisfy the requirements for treating a system as deenergized. A system is not properly deenergized until all of the hazardous energy control requirements in 1910.269(d) for generation installations or 1910.269(m) for transmission and distribution lines and equipment have been met and the system is properly grounded per 1910.269(n). Any system not meeting these requirements must be worked on as if it were energized. Energized work on electrical systems is performed in a number of ways:

1910.269 Photo credit: Oak Ridge National Laboratory

Energized Work: 1910.269(l)

Deenergized work: 1910.269(d) and 1910.269(m)

  • Typically workers wear insulating (rubber) gloves (with protectors) and also insulating sleeves (if required) when working on live systems.
  • In some instances, local ordinances, labor contracts, or company policy may require that workers use insulating live line tools (for example, hotsticks, switchsticks, and shotgun sticks) on primary distribution systems.
  • Live line/bare hand techniques are sometimes used for work on higher distribution voltages and transmission voltages.
  • Workers use Insulating Protective Equipment (IPE) such as line hose, blankets, and covers.

To perform energized work, workers must first be thoroughly trained and proficient in the work practices and protective equipment needed. Anyone who has not been trained and has not demonstrated proficiency is considered unqualified for 1910.269 purposes and cannot get closer to energized parts than the Minimum Approach Distances specified in 1910.333(c)(3) (also known as, the 10-foot rule) for the voltages involved. 1910.269-trained and - qualified employees must use appropriate protective equipment and work practices when they are within the Minimum Approach Distances in 1910.269(l)(2).

Minimum Approach Distances (MAD)
Hazardous Energy Control
Disabling of Reclosers and Remotely Operated Devices
Live Line/Bare Hand Work
Grounding for Employee Protection
Insulating Gloves and Sleeves
Insulating Protective Equipment