Cisco Systems ASR 903 manual Preventing Power Loss, Power Connection Guidelines

Chapter 3 Installing the Cisco ASR 903 Router

Installing the Power Supply

Preventing Power Loss

Use the following guidelines to prevent power loss to the router.

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

•In some systems, you can use an UPS to protect against power failures at your site. Avoid UPS types that use ferroresonant technology. These UPS types can become unstable with systems like the Cisco ASR 903 Router, which can have substantial current draw fluctuations due to bursty data traffic patterns.

Use the information in the “DC Power Specifications” section on page 1-4to estimate the power requirements and heat dissipation of a Cisco ASR 903 Router based on a given configuration of the router. Determining power requirements is useful for planning the power distribution system needed to support the router.

Power Connection Guidelines

This section provides guidelines for connecting the Cisco ASR 903 Router power supplies to the site power source.

Warning Never defeat the ground conductor or operate the equipment in the absence of a suitably installed ground conductor. Contact the appropriate electrical inspection authority or an electrician if you are uncertain that suitable grounding is available. Statement 213

Warning The plug-socket combination must be accessible at all times because it serves as the main disconnecting device. Statement 1019

Warning This product requires short-circuit (overcurrent) protection, to be provided as part of the building installation. Install only in accordance with national and local wiring regulations. Statement 1045

Guidelines for DC-Powered Systems

Basic guidelines for DC-powered systems include the following:

•Each chassis power supply should have its own dedicated input power source. The source must comply with the safety extra-low voltage (SELV) requirements in the UL 60950, CSA 60950, EN 60950, and IEC 60950 standards.

•The circuit must be protected by a dedicated two-pole circuit breaker. The circuit breaker should be sized according to the power supply input rating and local or national code requirements.

•The circuit breaker is considered the disconnect device and should be easily accessible.

•The system ground is the power supply and chassis ground.

•Do not connect the DC return wire to the system frame or to the system grounding equipment.

•Use the grounding lug to attach a wrist strap for ESD protection during servicing.

	Cisco ASR 903 Router Hardware Installation Guide
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