Nortel Networks 411-2021-111 manual 4Power and Grounding Requirements

5-4Power and Grounding Requirements

The input voltage for other communication equipment is typically -48 Vdc nominal. The voltage range at the Power Distribution Centre (or other type of a branch panel) shall not exceed the range between -43.75 Vdc to -55.80 Vdc.

The input power is usually obtained from a centralized plant, which may be shared with other systems or dedicated to the equipment.

Power plant batteries provide backup power for the equipment in case of power outage. The backup time is typically 8 hours at the site with no engine- alternator or 3 hours at the site with an emergency engine-alternator.

The grounding system of radio and transmission equipment typically conform to the Common Bonding Network (CBN) bonding topology.

Switching equipment conforms to the Isolated Bonding Network (IBN) grounding topology (typically, Star-IBN or Sparse-Mesh-IBN). Some systems also use a Star-IBN bonding topology where the Logic Return (LR) is isolated from the Framework Ground (FG) except at one clearly defined point.

411-2021-111 Standard 01.01 June 1996