Installing Power Modules | 195Installing Power ModulesThis chapter contains the following major sections:• Installing AC Power Modules• Installing DC Power Entry Modules on page 22• Power Supply and Fan Operability Test on page 27The E300 system requires a minimum of one DC Power Entry Module (PEM) or a minimum of two ACPower Supplies (see AC and DC Power on page 14 ).WARNING: The E300 must contain only one type of power module—AC or DC.WARNING: Electrostatic discharge (ESD) damage can occur when components are mishandled. Alwayswear an ESD-preventive wrist or foot-heal ground strap when handling chassis components.Installing AC Power ModulesThe E300 AC Power Supply Module is capable of operating at either 100 VAC or 220 VAC. If the E300is connected to a 100 VAC power supply, three power supply modules are required, or four power supplymodules are required for power supply redundancy.If the E300 is connected to a 220 VAC power supply, two power supply modules are required, threepower supply modules are required for power supply redundancy, and four power supply modules arerequired for full facility redundancy.For full facility redundancy, each power supply must be attached to an independent power source with adedicated circuit breaker sized in accordance with your local building and electrical safety codes. Tocomply with safety agency and emission requirements, a power supply blank cover must be inserted intoany unused power supply slot.CAUTION: Before removing and replacing a power supply module, determine if the E300 is in full facilityredundancy or non-redundant power. Operating in non-redundant power will require a complete system poweroff when removing and replacing a power supply.