Lightning Protection, Grounding,
& Surge Suppression Glossary of Terms

Your search returned:

Radial Ground
A conductor connection by which separate electrical circuits or equipment are connected to earth at one point. Sometimes referred to as a star ground.
Radio Frequency (RF)
Radio frequencies - any and all frequencies that can be radiated as an electromagnetic wave (plane wave).
Radio Frequency Interference (RFI)
RFI is manmade or natural, intentional or unintentional electromagnetic propagation which results in unintentional and undesirable responses from or performance degradation or malfunction of, electronic equipment.
Rated Peak Single-Pulse Transient Current
Maximum peak current that may be applied for a single 8/20 µs impulse, with rated line voltage also applied, without causing device failure.
Rated Single-Pulse Transient Energy
Energy that may be dissipated for a single impulse of maximum rated current at a specified wave shape, with rated root-mean-square (rms) voltage or rated DC voltage also applied, without causing device failure.
Rated Standby Power Dissipation
The power dissipated in a protective device while connected to an AC line having a voltage and frequency equal to the rating of the device and with no load current flowing and no surges applied.
Rated Voltage
The designated maximum permissible root-mean-square (rms) value of power-frequency voltage between its line and earth terminals at which it is designated to operate correctly.
Rating
The designation of an operating limit for a device.
Re-strike
High speed videos show that most lightning strikes are made up of multiple individual strokes. A typical strike is made of 3 to 4 strokes although there may be more. Each re-strike is separated by around 40 to 50 milliseconds, causing a noticeable "strobe light" effect.
Recovery Time
Specifies the time needed for the output voltage or current to return to a value within the regulation specification after a step load or line change.
Recovery Voltage
The voltage that occurs across the terminals of a pole of a circuit-interrupting device upon interruption of the current. NOTE: For an arrester, this occurs as a result of interruption of the follow current.
Red Sprites
A relatively new discovery, but now well-documented, these are electrical discharges that occur high above some types of thunderstorms. They appear as luminous reddish-orange or greenish-blue, plasma-like flashes, last longer than normal lower stratospheric discharges, and are triggered by the discharges of positive lightning between the thundercloud and the ground. Sprites often occur in clusters of two or more, and typically span the distance from 50 miles to 90 miles above the earth, with what appear to be tendrils hanging below, and branches reaching above.
Repetitive Surge And Follow-Current Withstand
The number of surges of specified voltage and current amplitudes and wave shapes that may be applied to a device without causing degradation beyond specified limits. The repetitive surge and follow-current withstand applies to a device connected to an AC line of specified characteristics and for pulses applied at specified rates and phase angles. The effects of any cumulative heating that may occur are included.
Resistive Coupling
The association of two or more circuits with one another by means of resistance mutual to the circuits.
Return Strokes
Those strokes occurring after the first return stroke in a multi-stroke flash. Also called re-strikes.
Reverse Standoff Voltage
The maximum voltage that can be applied across surge suppressor terminals with the surge suppressor remaining in a non-conducting state.
Ribbon Lightning
Ribbon lightning occurs in thunderstorms with high cross winds and multiple return strokes. The wind will blow each successive return stroke slightly to one side of the previous return stroke, causing a ribbon effect.
Ring Earth Electrode
An earth electrode forming a closed loop around the structure below or on the surface of the earth.
Ring Wave
An open-circuit voltage wave characterized by a rapid rise to a defined peak value, followed by a damped oscillation in which every successive peak has an amplitude of about 60% of the value of the peak that preceded it. For the 100 kHz Ring Wave, the rise time is nominally 0.5 µs and the ringing frequency is approximately 100kHz. No short-circuit current waveform is defined; the exact wave that is delivered is determined by the instantaneous impedance to which the Ring Wave is applied.
RMS Voltage
Applied to an AC sine wave, the RMS value is also known as the effective voltage and is .707 times the peak voltage.
Rocket Lightning
One of the rarest of cloud discharges, it is a form of cloud discharge, generally horizontal and at cloud base, with a luminous channel appearing to advance through the air with visually resolvable speed, often intermittently, with a movement that has been compared to a skyrocket.