Besides providing an organized and maintained neat work environment; having the right length of power cords will greatly improve your server room's performance by minimizing the amount of clutter in an enclosure, which increases air flow and with that the life of the equipment.
Power Adapter Cords
Power adapters are used to enable equipment with disparate input/output receptacles to work together. I.e. use a power adapter to connect an IEC C14 power plug to a NEMA 5-15 receptacle.
Power Jumper Cables
Jumpers are used to connect two pieces of equipment without cluttering up the cable arrangement; Jumper cables provide a power interconnect between the active component, such as a server, and a power distribution device such as a power distribution unit (PDU), an uninterruptible power supply (UPS), or an extension strip.
Power Cord Splitters
Splitters are used to add extra equipment to a UPS or PDU without using up more outlets. I.e. a splitter cable can be used to split (1) NEMA L21-30 plug into (3) NEMA L5-30 receptacles.