The right cable for an elevator: power motor and travelling cable

First say which part's cable we want

The phrase "elevator cable" can refer to the panel's incoming cable, the drive-to-motor connection, the fixed routes in the shaft or the cable that moves with the cab. These routes do not have the same function and stress. Choosing a cross-section for the supply should not be turned into choosing the core count of a travelling cable.

The elevator's electrical drawing and the documents of the elevator's maker, the panel and the drive are the basis for separating the routes. The purchase list should specify where each cable is installed, whether it is fixed or moving, and which circuits it carries. The number of stops or floors alone is not a full description of any of these routes.

What information does each route need?

A cable's name or the presence of a shield doesn't by itself prove the electromagnetic compliance of the whole installation. Routing, shield termination and equipment must be done to the design and relevant documents.

What extra features does a travelling cable have?

A travelling cable is designed to move with the cab. For a specific model, the maker can state the free hanging length, speed, operating temperature and loop shape. The cable may have a supporting member, power and control cores or data elements; not all models have these features equally.

In the referenced Datwyler example, the conductor class, data elements, supporting member and mechanical limits are recorded separately and the EN 50214 standard is also introduced. This example shows that choosing goes beyond counting cores; one model's numbers should not be generalized to all travelling cables.

Reference for this section: Datwyler: a sample travelling cable and its mechanical and electrical specifications

How do we bring the cab camera and network into the request?

If the cab has a camera, a network or communication equipment, the type of communication and its needs must be settled in the cable design from the start. Having a few spare cores does not guarantee that every kind of signal can be carried on them at the quality required.

Some makers offer multimedia travelling cables with defined data elements. For example, Datwyler has introduced the combination of data cable and fiber in one product. This is no permission to use a fixed-installation network cable in a moving loop; the communication element must also be chosen to suit movement and connection.

Reference for this section: Datwyler: separating the power and data elements in a travelling cable

A coordination checklist before ordering

• The location of each route and whether it is fixed or moving.
• The specifications of the panel, motor and drive and the connection diagram.
• The travel height, free hanging length and design speed for the travelling cable.
• The number and size of conductors, the control circuits and the communication needs.
• The fire requirements, the environment and the project's acceptance documents.

Substituting one model for another must be agreed with the technical lead and the system's maker. Inspecting cable in an elevator shaft is not a job for an ordinary user; for a visit or to fix a fault, get help from an authorized service and maintenance company. The softness of a is not a reason for its suitability for this use.

Information you should get from the elevator company

Before ordering, get the specifications from the elevator company or the equipment's maker; guessing the cable type from the elevator's capacity is not enough.

Maintaining and inspecting a travelling cable

A travelling cable bends and releases as the cab moves; so how it is hung and how twisting is prevented matter. The exact method must follow the cable maker's and the elevator's instructions.

• During installation, unreel the cable without twisting and let the hanging points spread the load.
• Look at the sheath in periodic inspections for abrasion, crushing or cracking.
• Tell the elevator company about any change in length, hanging point or an added circuit (such as a camera).

Frequently asked questions