Is There a Restriction on the Length of Cable, Chain or Solid Bar Used on Hanging Light Fixtures?

There is no restriction when adding cable and chain. If the fitting is made with a solid rod there will be restrictions to the overall height, as the longer the bar the more unstable it becomes.

 
If you require a solid bar of more than 1 meter (39 inches) length we may need to use a thicker rod to improve the stability, generally we would not advise using a solid rod for a drop of more than 2-3 meters (79-118inches).