Electrical Safety Requirements for Cranes and Lifting Equipment

ITC-BT-32: Electrical Installations for Lifting and Transport Machinery

1. Scope of Application

This instruction addresses the particular requirements for installation systems of electrical equipment used in cranes, lifting equipment, transport, and other similar machinery such as escalators, conveyors, bridge trailers, winches, and electrical scaffolds.

3. Protection to Ensure Safety

3.1. Protection Against Direct Contact

Collecting systems, sets of slip rings, cables, bus bars, and runway assemblies must be locked or positioned so that personnel accessing relevant areas of the facility (e.g., corridors of the sliding guides or crane girder aisles, including access points) are protected against direct contact with live parts.

3.2. Overcurrent Protection

The electrical equipment must be protected by one or more automatic protective devices that activate in case of an overcurrent caused by overload or short circuit. This requirement does not apply to equipment designed to inherently withstand current surges.

• The operation of the overcurrent protective devices for mechanical brake actuators must produce simultaneous disconnection of motion for the actuators.
• Over-temperature protective devices that include temperature-sensitive elements mounted in or on the motor windings, when combined with a contactor, cannot be regarded as sufficient protection against a short circuit current.

4. Isolation and Disconnection

4.1. Isolation for Mechanical Maintenance

The isolation switches must be all-pole (omnipolar) and must include means to prevent the unexpected re-energizing of the installation. A switch must be installed on the supply side of the slip rings or bus bars to allow the isolation and disconnection of all line conductors and the neutral wire of the installation.

4.2. Disconnection and Emergency Stop

Each crane, lifting device, or transport system must have one or more emergency stop mechanisms accessible from all operating positions. When multiple circuits are involved, the emergency stop mechanisms must be designed so that a single action causes the disconnection of all relevant power supplies.

6. Provision of Earthing and Protective Conductors

When power is supplied through collector cables, bus bars, or sets of slip rings, the protective conductor must utilize an individual slip ring or busbar. The supports for this protective conductor must be clearly visible and distinguishable from those of the live rings or busbars (assets).

In environments exposed to corrosive gases, humidity, and dust, special protective measures must be applied to the collector rings, bars, or rails used as protective conductors.

The protective conductor must not carry any current during normal operation.