An AC PEM includes a power inlet, EMI filter and backplane connectors. Power input to the system is fed via a PEM (Power Entry Module) through backplane into the power supply. Each AC power module has its own dedicated power cable. The on/off switch on the rear of the RMX activates any power module installed on the RMX. An AC system has three AC PEMs, one for each power module. On failure, both AC power supplies and PEMs are hot swappable.