IEEE Std 1590:2003 pdf free download.IEEE Recommended Practice for the Electrical Protection of Optical Fiber Communication Facilities Serving, or Connected to, Electrical Supply Locations.
Several power companies require special grounding and the placement of pole-mounted isolation transformers in series with the commereial power to mitigate the hazard (see Rajotie et al lB 191). The Y grounded distribution system is stepped down from the primary voltage to 120 V ac and then transmitted in an ungrounded configuration to a 120 V grounded isolation transformer with a BIL of 100000 V or greater (see Figure 1). This design allows the wireless equipment to have a neutral grounded electrical system that will provide a return path to the low-voltage isolation transfornier. This provides safe operation on their ground grid and isolation for the high-voltage return current associated with a line-to-ground fault of the transmission voltage.
6.3 Electric field induction
Ungrounded telecommunications cables and hardware, as well as personnel, located in the vicinity of high-voltage power transmission lines may become electrically energized by electrostatic coupling to the high-voltage power line. An ungrounded object, including a person. will assume a potential relative to the earth, based on the power line voltage and geometry, and the capacitance of the object or person with respect to both the power line and the earth (5cc Tl.3l6- 1997 1B201).
Personnel working near high-voltage lines may become charged by the electric field surrounding the lines. The voltages can be large. and the available current is usually small, below the level that may cause electrical injury. The electric shock or arc obtained may be startling. causing accidental injury as a result of involuntary reaction.
Grounding of telecommunications plant and hardware helps to minimize the possibility for injury because of involuntary reactions by keeping the cables and hardware and the earth near them at the same potential.
6.4 Emergency engine generating units
The emergency engine generator shall be installed in accordance with the requirements of the NEC for a separately derived system.
Engine generators shall be used to provide ac power only on a temporary basis (less than 45 days) while waiting for permanent utility ac power or until service is restored alter a service outage.
Temporary installations shall comply with the following restrictions:
— The engine generator and any separate aboveground metallic fuel storage container shall he effectively bonded to the site’s grounding system.
— Buried grounding rings or temporary grounding mats shall be installed around the engine generator and any metallic fuel storage container.
Whenever practical, refuel equipment off the power line easement or fec-owned property to eliminate arcing. When not practical. Lnansftr flammable liquids between metal containers only after electrically bonding the containers together to eliminate the potential for arcing ignition of the fuel.