6 Four-Post Rack Installation• Make sure that the rack is level and stable before extending a component from the rack.• Use caution when pressing the component rail release latches and sliding a component into or outof a rack; the slide rails can pinch your fingers.• Do not overload the AC supply branch circuit that provides power to the rack. The total rack loadshould not exceed 80 percent of the branch circuit rating.• Ensure that proper airflow is provided to components in the rack.• Do not step on or stand on any component when servicing other components in a rack.General Installation InstructionsThis installation guide provides instructions for trained service technicians installing one or more systemsin a rack cabinet. The RapidRails™ rack kit can be installed in all the system manufacturer's rack cabinetswithout tools, and the VersaRails™ rack kit can be installed in most industry-standard rack cabinets. Theprocedures for installing both RapidRails and VersaRails rack kits are similar. One rack kit is required foreach system to be installed in the rack cabinet.This section includes procedures for the following four-post rack kits:• Sliding rails rack kit• Static rails rack kit (RapidRails and VersaRails versions)(See "Two-Post Rack Installation" on page 27 for instructions on installing a static rails kit in a two-postrack.)Before You BeginBefore you begin installing your system in the rack, carefully read "Safety Instructions," found earlierin this guide, as well as the safety instructions found in your Product Information Guide for additionalinformation.CAUTION: When installing multiple systems in a rack, complete all of the procedures for the current systembefore attempting to install the next system.CAUTION: Rack cabinets can be extremely heavy and move easily on their casters. They do not have brakes. Useextreme caution while moving the rack cabinet. Retract the leveling feet when relocating the rack cabinet. Avoidlong or steep inclines or ramps where loss of cabinet control may occur. Extend the leveling feet for support andto prevent the cabinet from rolling.NOTE: For instructions on installing the system itself, see ""Installing the System in the Rack" on page 18.