Firming up the Framing Why and How to Stiffen the Telecommunications Cabling Infrastructure

Abstract

The intent of this paper is to show the need for adequate bracing and framing of cable trays in the central office environment, particularly cable racks bearing power cables. Power busbars and cabling are the densest conductors in the telecommunications environment and everything in the central office is dependant on power. The paper will cover seismic influences on the cabling structures and the ways in which seismic displacement could result in systemic failure of the telecommunications systems if the mechanical support for the cabling or buswork is inadequate. The paper also will cover bracing and framing for busbars and busduct systems with text and illustrations. The paper will cover bracing and framing for cable trays including primary and secondary power cables, communication cables and optical fiber cable trays. Most telecommunications huts and CEVs are equipped with adequate cableways and so this paper is intended to speak mainly to central office cabling whether for wireline or wireless use and for data centers with DC powered systems. Finally, the paper will socialize an idea in the telecom community. Unfortunately, the way the National Fire Protection Association (NFPA) has written the codes, only plenum rated cables may be run beneath the floor if that floor also is used as a cooling air plenum. The requirement is because toxic gasses from burning cabling insulation being pushed into the working space occupied by employees were a fire to ignite beneath the floor. However, Telco's now have a twenty year history of successfully using Very Early Smoke Detection Alarm (VESDA) systems. Many of these systems are designed to sample room air through PVC pipes placed under partial vacuum and then route that sampled air past a particle counter