New Cable Requirements for Large Wind Turbines

Wiring changes are looming for wind turbines.

The electrical systems on large wind turbines will soon be subject to a new standard, UL 6141, which could result in drastic changes to cabling practices. The standard applies to both new and refurbished wind turbines that generate more than 500 kilowatts of power. 

While UL 6141 has not yet been finalized, it proposes strict limits on the use of appliance-wiring material (AWM) within and between key generator subsystems.

The limits spring from a requirement that all accessible wiring must be either enclosed in a raceway or rated for tray cable usage. Since only UL listed cable offer the tray rating, AWM will no longer make the grade in many turbine wiring applications.

Here’s a breakdown of how the new standard will likely affect the different wind turbine subsystems:

Gearbox. There is no UL component standard specifically for gearboxes, so UL 6141 will apply to the wiring for gearbox components such as heaters and PT 100 temperature sensors.

Generators. The existing UL component standard for generators permits AWM cables under limited circumstances. To use AWM in generator wiring, there must be a ready-to-connect cable with connector. The generator must also be fitted with a grounding cable within the generator itself.  Since neither option is common with wind turbine generator manufacturers today, UL listed cable products will likely be the safest design strategy once UL 6141 comes to pass.

Tower. Since there is no UL component standard for the tower, UL 6141 applies. The proposed standard clearly calls for listed products for cables that run vertically up the tower—including those for power, control signals, lighting and hoists.

Drip Loop. Raceways are not commonly used in drip loops.  Assume that listed cable products will have to be used in this application.

To learn more about all the changes UL 6141 will bring, download our technical update.