High Voltage Environments

Working with cranes, derricks, and other hoisting equipment can pose electrical hazards, including electrocution. Clearance, grounding, and disconnection must be taken seriously.

Grounding

Properly grounding a crane or other equipment includes the following actions:

• All exposed metal parts of cranes and hoists are joined together (with metal) in order to create a continuous electric current.
• Except for removable accessories or attachments, moving parts with metal-to-metal bearing surfaces "must be considered to be electrically connected to each other through the bearing surfaces for grounding purposes."
• The trolley frame and bridge frame are considered to be electrically grounded (via bridge and trolley wheels and their respective tracks), except when conditions such as paint or other insulating materials inhibit metal-to-metal contact. (In this case, there must be a separate bonding conductor.)

See §1926.404(f) for details on grounding equipment.

Disconnecting

Obeying proper electrical protocol includes having the following:

• A means for runway conductor disconnection located between the runway contact conductors and the power supply.
• A disconnecting means for cranes and monorail hoists that can be locked in the open position (also between the runway contact conductors and the power supply).
• A limit switch or other device to prevent the load block from passing the safe upper limit of travel of any hoisting mechanism.

Consult §1910 Subpart S (titled "Electrical") for other electrical safety requirements for employees.

To learn more about Crane, Derrick & Hoist visit our Crane, Derrick & Hoist Safety Online Training web page.