Enlightenment about Lightning Protection Terms (Decoding the code jargon!)

Every profession and field of endeavor subscribes to its own jargon, which can be a source of serious frustration for those unfamiliar with the insider lingo.

The world of lightning protection is no exception. Unfortunately, the language of lightning protection installation can be a source of confusion for consumers and homeowners trying to decipher and understand the industry jargon. In an attempt to decode the code language, here’s a “Glossary” to enlighten readers about a few commonly-used lightning protection terms.

Note: language referenced below is as defined by the Lightning Protection Institute Standard of Practice for the Design – Installation – Inspection of Lightning Protection Systems, LPI-175/2017 Edition

Glossary of Lightning Protection Terms

Authority Having Jurisdiction: The organization, office, or individual responsible for approval and enforcement of equipment, materials, and installation or a procedure.

Bonding: An electrical connection between an electrically conductive object and a component of a lightning protection system that is intended to significantly reduce potential differences created by lightning currents.

Cable: A factory assembly combining multiple wire strands together to form a single conductor.  

Conductors: Devices defined by this Standard (LPI-175) as suitable to carry lightning current or make bonding interconnections.

Fastener: A component or set of components used to securely attach materials to the structure.  (Kim’s note: 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.)

Grounded: Connected to earth or to some conducting body that is connected to earth ground.

Grounding Electrode: The portion of a lightning protection system, such as a ground rod, ground plate or ground conductor that is installed for the purpose of providing electrical contact with the earth. (Kim’s note: grounding electrode applications must be suitable for soil conditions present at the location for the lightning protection system installation.)

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. (Kim’s note: equipment and materials are labeled for quality control purposes.)

Lightning Protection System: A complete system of strike termination devices, main conductors (including conductive structural members), grounding electrodes, bonding or interconnecting conductors, surge protection 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 listed equipment or materials, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. (Kim’s note: lightning protection components are typically, “UL-listed” for quality control purposes and contractor firms are typically UL-listed to install lightning protection systems.)

Strike Termination Device (Air terminal): A 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 (overhead shielding), lightning protection systems.

Surge Protective Device (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 that comprises at least one nonlinear component. (Kim’s note: SPD’s are also described as “lightning arresters, surge arresters, surge suppressors and TVSS” in the field. SPD’s are typically installed in service electrical panels to block or ground lightning’s harmful voltage.)

 Zone of Protection: The space adjacent to a lightning protection system that is substantially immune to direct lightning flashes.