LPI Definitions

Strike termination device that is a lightning receptor for attachment of flashes to the lightning protecion system and is listed for the purpose.

Acceptable to the authority having jurisdiction

The organization, office, or individual responsible for approval and enforcement of equipment, materials, an installation, or a procedure.

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.

A conductor used for potential equalization between grounded metal bodies or electrically conductive objects and a lightning protection system. The bonding conductors are normally smaller in size than current carrying conductors.

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

A lightning protection system consisting of one or more overhead ground wires. (also known as overhead shielding)

A structure containing one or more vertical or nearly vertical passageways for conveying flue gases to the outside atmosphere.

Air terminals, conductors, grounding electrodes, and associated fittings required for the protection of structures not exceeding 75 ft

Air terminals, conductors, gorunding electrodes and associated fittings required for the protection of structures exceeding 75 ft.

A surge generator with a 2 ohm internal impedance producing a 1.2/50 us open circuit voltage and an 8/20 short-circuit current wave shape.

Devices defined by this Standard as suitable to carry lightning current or make bonding interconnections.

Steel rod or wire with a coating of copper bonded it.

A component or set of components used to securely attach materials to the structure.

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

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.

A smoke or vent stack with a flue that has a cross-sectional area greater than 500 square inches and a height greater than 75 feet.

A complete system of strike termination devices, main conductors, grounding electrodes, bonding or interconnecting conductors, surge protection devices and other connectors or fittings required to complete the system.

A conductor encircling a structure that is used to interconnect grounding electrodes, main conductors and or electrically conductive bodies.

A conductor intended to be used to carry lightning currents between strike termination devices and grounding electrodes.

Maximum Continuous Operating Voltage

The maximum designated rms value of the power frequency voltage that can be continuously applied to the mode of protection of a surge protection device.

Surge Protection Device

The maximum instantaneous value of the current through the SPD having a 8/20 us waveform.

Maxium Discharge Current

Measure Limiting Voltage

Maximum magnitude of voltage that is measured across the terminals of the surge protective device during the application of impulses of specified waveshape and amplitude.

A structure with sides or roof or both covered with metal.

A structure with electrically continuous structural members of sufficient size to provide an electrical path equivalent to that of lightning conductors.

Nominal Discharge Current

Peak value of 8/20 us current waveform selected by the manufacturer for which an SPD remains functional after 15 surges.

The nominal voltage (rms) of the power frequency supply.

The normal ac power frequency voltage rating, as specified by the manufacturer, to which the surge protection device may be connected.

An electrical spark, caused by differences of potential that occurs between conductive metal bodies or between conductive metal bodies and a component of a lightning protection system or ground.

Any short air space between two conductors that are electrically insulated from or remotely electrically connected to each other.

A transient wave of current, potential or power in an electric circuit. Surges do not include longer duration temporary over voltages (TOV) consisting of an increase in the power frequency voltage for several cycles.

Temporary Over Voltage

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

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 cicuit voltage of 6kV and a shortcircuit current of 3 kA. The value is rounded up to the next highest 100 V level.

The space adjacent to a lightning protection system that is substantially immune to direct lightning flashes.

A surge gnerator with 2-ohm internal impedance producing a 1.2/50 us open circuit voltage and an 8/20 us short-circuit current wave shape.

Cross-sectional area of the flue is greater than 500 in² and a height greater than 75 feet

Electromagnetic effects of lightning current, which includes conducted surges as well as radiated impulse electromagnetic field effects.

An electrical spark, caused by differences of potential

any short air space between two conductors that are electrically insulated from or remotely electrically connected to each other

A subcycle disturbance in teh ac waveform that is evidenced by a sharp, brief discontinuity of the waveform. It can be of either polarity and can be additive to, or subtractive from, the nominal waveform.

The maximum designated rms value of the power frequency voltage that can be continuously applied to the mode of protection of a surge protection device.

Maximum magnitude of voltage that is measured across the terminals of the surge protection device during hte application of impulses of specified waveshape and amplitude.

The nominal voltage (RMS) of the power frequency supply.

The normal ac power frequency voltage rating, as specified by the manufacturer, to which the SPD may be connected.

A rating 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 shortcircuit curret of 3 kA. The value is rounded up to the next highest 100 V level.