Glossary of Terms

These terms are defined by the Lightning Protection Institute Standard of Practice – LPI-175/2008 Edition.

AUTHORITY HAVING JURISDICTION: The organization, office, or individual responsible for approving equipment, materials, an installation or procedure.

BONDING: The permanent joining of metallic parts to form an electrically conductive path that will ensure electrical continuity and the capacity to conduct safely any current likely to be imposed.

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 conductor strands.

CATENARY LIGHTNING PROECTION SYSTEM: A lightning protection system consisting of one or more overhead ground wires (also known as “overhead shielding”).

CONDUCTORS: Devices defined by the standard as suitable to carry lightning current. This may include strike termination devices, cables, lightning protection fittings, ground terminals, or metallic structural members.

FASTENER: A component or set of components used to securely attach materials to the structure. A fastener may also be a mechanical device, such as a rivet, bolt, screw, or pin that is used to securely hold two or more components together.

GROUND ELECTRODE: The portion of lightning protection system, such as a ground rod, ground plate electrode, or ground conductor that is installed for the purpose of providing electrical contact with the earth.

LABELED: Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled 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 authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials, or service meets appropriate designed standards or has been tested and found suitable for a specified purpose.

STRIKE TERMINATION DEVICE (AIR TERMINAL): A component of a lightning protection system that intercepts lightning flashes and connects them to a path to the ground. Strike termination devices include air terminals, metal masts, and permanent metal parts of structures as described in LPI-175 and overhead ground wires installed in catenary lightning protection systems.

SURGE PROTECTIVE DEICE (SPD): A device composed of any combination of linear or nonlinear circuit elements intended for limiting surge voltages on equipment by diverting or limiting surge current.

TRANSIENT VOLTAGE SURGE SUPPRESSOR (TVSS): A surge protective device for limiting transient voltages by diverting or limiting surge current; it also prevents continued flow of follow current while remaining capable of repeating these functions.

VOLTAGE PROECTION 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 100 V level.

ZONE OF PROTECTION: The space adjacent to a lightning protection that is substantially immune to direct lightning flashes.

Typical Commercial Lightning Protection System Components:

ADHESIVE BASE/ADHESIVE CABLE FASTENER: Holds the air terminal assembly in place, while connecting and fastening the cable conductor to the structure.

UL MASTER LABEL: Signifies that the lightning protection system was inspected to comply with UL installation standards. (Note: UL automated its inspection services in 2003 and began issuing certificates via the Internet to replace the metal Master Labels. Effective 4/12/07, UL revised wording to: “UL Lightning Protection Inspection Certificate.”)

SURGE PROTECTIVE DEVICE (SPD): A device composed on any combination of linear or nonlinear circuit elements intended for limiting surge voltages on equipment by diverting or limiting surge current.

CABLE CONNECTOR: Fittings used for the bonding or connection of down conductors and/or grounding equipment. (Bimetallic connectors must be used for splicing or bonding of dissimilar metals.)

PIPE CLAMP: Used to connect underground metallic piping systems.

BOLT FITTING: A parallel cable connector which ensures continuity.

SIDE MOUNT BASE: Adhesive cable fastener used to side mount air terminals for placement on a structure’s wall.

THROUGH-ROOF ASSEMBLY: Used to achieve a through-roof connection to the grounded steel framework.

BOLT FITTING AND GROUND TERMINATION: Used for steel column grounding connections.