Powered manlift or aerial devices vary in cost, complexity and size from a simple truck mounted ladder to 150 foot devices mounted on crane carrier chassis.
Considerations pertinent to the purchase of one are - height of work to be performed, insulated or non-insulated, load to be lifted, required side reach, travel height, number and span of outriggers, and whether the unit should articulate fully, non-overcenter or be a telescoping boom. Ease of maintenance is also a consideration.
Articulated units often give a better choice of working positions and facilitate field side work.
Telescoping units are generally preferred when working through heavy trees.
The purchase of a device larger than required can squander much capital both in the device itself and in the chassis required to mount the device.
Consideration must also be given to whether or not plant is to be placed from the unit and what type of tooling will be used in conjunction with it.
The upper portion of the device will need to be dielectric for electric utilities and the working voltage must be decided upon and specified as well as whether or not a dielectric liner is to be used.
The buyer should be aware of existing O.S.H.A. and A.N.S.I. standards applying to aerial devices.