Figure 102. Installing a power supply unitNext steps1 If you have unlatched the cable management arm, relatch it. For information about the cable management arm, see the system’s rackdocumentation at Dell.com/poweredgemanuals.2 Connect the power cable to the PSU, and plug the cable into a power outlet.CAUTION: When connecting the power cable to the PSU, secure the cable to the PSU with the strap.NOTE: When installing, hot swapping, or hot adding a new PSU, wait for 15 seconds for the system to recognize thePSU and determine its status. The PSU redundancy may not occur until discovery is complete. Wait until the new PSUis discovered and enabled before you remove the other PSU. The PSU status indicator turns green to signify that thePSU is functioning properly.Wiring instructions for a DC power supply unitYour system supports up to two –(48–60) V DC power supply units (PSUs).WARNING: For equipment using –(48–60) V DC power supply units (PSUs), a qualified electrician must perform all connectionsto DC power and to safety grounds. Do not attempt connecting to DC power or installing grounds yourself. All electrical wiringmust comply with applicable local or national codes and practices. Damage due to servicing that is not authorized by Dell is notcovered by your warranty. Read and follow all safety instructions that came with the product.CAUTION: Wire the unit with copper only, unless otherwise specified, use only 10 American Wire Gauge (AWG) wire ratedminimum 90ºC for source and return. Protect the –(48–60) V DC (1 wire) with a branch circuit over-current protection rated 50A for DC with a high interrupt current rating.CAUTION: Connect the equipment to a –(48–60) V DC supply source that is electrically isolated from the AC source (reliablygrounded –(48–60) V DC SELV source). Ensure that the –(48–60) V DC source is efficiently secured to earth (ground).NOTE: A readily accessible disconnect device that is suitably approved and rated shall be incorporated in the field wiring.Input requirements• Supply voltage: –(48–60) V DC152 Dell EMC PowerEdge R740 Installation and Service ManualInstalling and removing system components
