| LIGHTNING PROTECTION GLOSSARY OF TERMS |
| The following terms are defined by the Lightning Protection Institute (LPI) 175, Standard of Practice for Design, Installation, and Inspection:
Authority having jurisdiction (AHJ): The organization, office, or individual responsible for approving equipment, materials, an installation, or procedure. Bonding: An electrical connection between an electrically conductive object and a component of a lightning protection system intended to significantly reduce potential differences created by lightning currents. Bonding conductor: A conductor used for potential equalization between grounded metal bodies or electrically conductive objects and a lightning protection system. Cable: A factory assembly combining multiple wire strands together to form a single conductor. Catenary lightning protection system: A lightning protection system consisting of one or more overhead ground wires (also known as ‘overhead shielding’). Conductors: Devices defined by LPI 175 as suitable to carry lightning current or make bonding interconnections. Fastener: A component (or set) used to securely attach materials to the structure. Ground electrode: The portion of a lightning protection system, such as a ground rod, ground plate, or ground conductor installed for the purpose of providing electrical contact with the earth. Labelled: Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the AHJ and concerned with product evaluation, that maintains periodic inspection of production of labelled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner. Lightning protection system: A complete system of strike termination devices, main conductors (including conductive structural members), grounding electrodes, bonding or interconnecting conductors, surge suppression devices, and other connectors or fittings required to complete the system. Listed: Equipment, materials, or services included in a list published by an organization that is acceptable to the AHJ and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. Strike termination device (air terminal/rod): Component of a lightning protection system that intercepts lightning flashes and connects them to a path to ground. Strike termination devices include air terminals, metal masts, qualified permanent metal parts of structures as described in LPI 175, and overhead ground wires installed in catenary lightning protection systems. Surge protective device (SPD): A device intended for limiting surge voltages on equipment by diverting or limiting surge current that comprises at least one nonlinear component. Transient voltage surge suppressor (TVSS): A subcycle disturbance in the ac waveform that is evidenced by a sharp, brief discontinuity of the waveform— it may be of either polarity and may be additive to, or subtractive from the nominal waveform. Voltage protection rating (VPR): A rating (or ratings) selected by the manufacturer based on the measured limiting voltage determined when the SPD is subjected to a combination waveform with an open circuit voltage of 6 kV and a short-circuit current of 3 kA. The value is rounded up to the next highest l00 V level. Zone of protection: The space adjacent to a lightning protection system that is substantially immune to direct lightning flashes. |
Kim Loehr is communications director for the Lightning Protection Institute (LPI) and a partner member of the National Oceanic and Atmospheric Administration/National Weather Service (NOAA/NWS) Lightning Safety Awareness Team. She is also a member of the (NFPA’s) Building Fire Safety Systems section. Loehr can be reached via e-mail at kiml@lightning.org.
