Figure 8 Bar Electrification and Festoon Electrification

     Figure 8 bar appeared on the scene as an electrification method for hoists and cranes over 50 years ago. It remains an industry standard in the U.S. for electrification of overhead crane runways and monorail systems.  Since bridges, trolleys, and hoists move during operation there must be some appropriate means to provide power to them all along the system. Not many years ago cranes were electrified by collector shoes or wheels sliding or rolling against exposed conductors or bare copper wire. This was recognized as an unsafe practice and current safety regulations prohibit this type of electrification for new cranes. The next stage of development was to replace the bare wire with an insulated bar and sliding shoe collector system. This was, and still is, called figure 8 bar because the bar inside the insulation when viewed from the end looks like a figure 8. Although this was an improvement and removed most of the exposed conductor safety hazard, the shoes wore out and contact was not direct.