Drum type winches - A common practice is using the same drum puller for overhead and underground, or a bed winch, to pull in the URD conductor.
A drum-type puller or winch has no way to monitor actual line tension.
Also, the maximum pulling capacity is obtained when the drum is empty.
As the drum fills up with power cable, the speed increases, and the pulling tension decreases.
At the end of the pull when the drum is full, the winch is at its minimum capacity, and that is when the pull is at its maximum tension.
Bullwheel type pullers - A puller with bull wheels maintains the same speed and tension when the drum is empty as when the drum is full.
The actual drum on this type of puller is merely a storage drum with no effect on the speed or tension.
Underground pullers - A puller designed specifically for underground normally has a dynamometer and footage counter to allow the operator to monitor and maintain desired pulling tensions and speeds for safe and efficient cable installation.