Power supplies installed on the switch chassis can be all AC-input, all DC-input, or a mix of both. When preparing your site for switch installation, adhere to these requirements.

• In systems that are configured with more than one power supply, connect each of the power supplies to a separate input power source. If you fail to do this, your system might be susceptible to total power failure due to a fault in the external wiring or a tripped circuit breaker.

• To prevent loss of input power, ensure that the total maximum load on each source circuit is within the current ratings of the wiring and breakers.

• You can also use an uninterrupted power supply (UPS) to protect against power failures at your site. However, some UPS models that use ferroresonant technology may become unstable when operating with the switch power supplies that use power factor correction. This may cause the output voltage waveform to the switch to become distorted, resulting in an undervoltage situation in the system.