Glossary

Glossary of terms.

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


AC – Alternating Current – Electrical current that continually reverses direction, with this change in direction being expressed in Hertz, or cycles per second.

Ampere – Quantitative unit of measurement of electrical current. Abbreviated as Amp or A.

ANSI C62.41-1991 – A technical Standard dealing with the electrical powerline surge environment and originally published by the Institute of Electrical and Electronic Engineers (IEEE) as IEEE 587 in 1980, updated in 1991 and now recognized as an American National Standard.

Arc Fault Circuit Interrupter (AFCI) – A type of duplex receptacle or circuit breaker that breaks the circuit when it detects a dangerous electrical arc in order to prevent electrical fires.

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Capacitor – An electrical component which stores electrical voltage, and also resists electrical voltage changes.

Certification – The Federal government, UL and other agencies establish Standards of safety and performance. Testing labs such as ETL and UL can Certify said performance, endurance, and safety.

Commercial Item Description (CID) – The Federal government develops CIDs for purchasing commercially available products. In 1996, they issued a CID for the purchase of powerline surge suppressors with Grade A, Class 1, Mode 1 being the highest rating.

Clamping Level (Clamping Onset Level) – This generally is used to describe the voltage level which causes the surge diversion device to start to divert surge energy. A related, but more important parameter is the Suppressed Voltage.

Clamping Time – The response time it takes a surge suppressor to go from its “off” condition to “on” condition in clamping or diverting surges when a surge voltage exceeds the clamping onset level.

Class 1, Class 2, Class 3 – Let-through voltage, or Suppressed Voltage Rating (SVR) performance Classes defined by the Federal government CID in their powerline surge suppressor specification. Class 1 products have a SVR of 330 volts (the best rating). Class 2 products have a SVR of 400 volts, and Class 3 have a SVR of 500 volts. The Class of a given product may change depending on the Grade it is tested to, since the test conditions are different for different Grades, and this may influence the SVR, hence the Class.

Combination Pulse – A high energy test pulse specified by ANSI C62.41-1991. Also called a “unipolar pulse”.

Common Mode Voltage – A voltage on the neutral wire of the power wiring, compared to the ground wire, where the ground wire is assumed to be the reference.

Current (expressed in units of amperes, or simply amps) – Current is the electrical equivalent of water flow. Current will flow in a circuit when the applied voltage exceeds a certain level, as dictated by the various components in the electrical circuit.

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DC – Direct Current – Electrical current which flows in one direction.

Degradation – Undesirable performance changes.

Disruption – Undesirable disturbance.

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EMI – Electro-Magnetic Interference – Electrically induced noise or transients.

Energy (expressed as joules or watt-seconds) – 1 joule = 1 watt-second. This measure of energy is the product of electrical power and time. A 60 watt light bulb turned on for 1 second expends 60 joules of energy.

ETL Listed Mark – proof that a product has been independently tested by Intertek and meets the applicable published North American safety standard.

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Fault – A fault is a wiring problem such as a broken wire, or wires touching typically due to storm damage, requiring physical repair.

Filter – An electronic device that allows only certain frequencies to pass.

Frequnecy – Voltage can be continuous (Direct Current or DC) or alternating (AC). The frequency of alternating voltage is the number of times per second that it changes polarity from positive to negative. Most power voltage in the US is delivered at 60 Hertz (60 changes from positive to negative per second).

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Grade A, Grade B, Grade C – The Federal CID defined three grades of surge suppressors based on endurance testing at several surge test levels. Grade A is for 1,000 surge endurance with 6,000 volts, 3,000 amperes applied. Grade B is for 1,000 surges with 4,000 volts, 2,000 amperes. Grade C is for 1,000 surges with 2,000 volts, 1,000 amperes applied.

Ground – For safety reasons, electrical systems in the USA have a wire connected to earth ground at the service entrance. This “ground” wire is run along with the two current carrying wires. Most electrical equipment is electrically connected to this wire when a three wire plug is used to connect the equipment to the electrical power receptacle. This third, non current carrying conductor which is connected to earth ground at the service entrance of a building is often referred to as “ground”.

Ground Consumption – The designers of electrical equipment assume that equipment connected to the electrical ground wire are at “ground potential”, that is, all at the same voltage. When equipment is electrically interconnected with audio, video, or data cables, and surges or other noise is injected into the ground wire, ground contamination occurs.

Ground Fault Circuit Interrupter – a type of duplex receptacle or device that shuts off an electric power circuit when it detects that current is flowing along an unintended path, such as through water or a person.

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Hertz – Unit of measure of the frequency of alternating current.

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IEEE 587-1980, ANSI C62.41-1991 – A technical Standard originally published by the Institute of Electrical and Electronic Engineers (IEEE) in 1980, updated in 1991, and now recognized as an American National Standard.

Impedance – Similar to electrical resistance since it is a measure of the opposition to the flow of electricity. Impedance is meaningful only for alternating current, and changes value as the frequency of the electricity changes.

Inductor – An electrical component which opposes the flow of electric current. An inductor has the property of impedance, the opposition to the flow of electric current. Impedance changes value with the frequency of the applied electricity.

Interconnected Equipment – Equipment which shares at least 1 common electrical connection other than the power wires. A printer and a computer share a “printer cable” for instance.

Internet of Things (IoT) – the Internet working of electronic devices embedded with electronics, software, sensors, actuators, and network connectivity enabling the objects to collect and exchange data.

Intersystem Bonding Termination – A device that provides a means for connecting bonding conductors for communications systems to the grounding electrode system. The ground lines of your building’s cable TV, phone, fire alarm systems, and power systems are all bonded together along with the power system neutral at the service entrance.

Intertek – a nationally recognized testing laboratory ensuring products meet quality, health, environmental, safety, and social accountability standards for virtually any market around the world.

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Joules – A unit of energy, also known as watt-seconds. Some suppressors are rated in joules, meaning that if a surge exceeds the joule rating, the suppressor will likely be damaged. The joule rating of many suppressors deteriorates with use.

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Load – An electrical device connected to a power source.

Let-Through Voltage – The peak voltage that is let through a surge protection device from a surge to the protected equipment. The theoretical lower limit is about 180 volts peak for standard 120 volt AC power. Lower is better. Also called SV (Suppressed Voltage) by UL. An important measure of suppressor performance.

Local Area Network (LAN) – An interconnection of computers, printers and other peripherals permitting the sharing of hardware and software resources.

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Maximum Continuous Operating Voltage (MCOV) – the magnitude limit of continuously applied voltage.

Metal Oxide Varistor (MOV) – A component which behaves like a low value resistor when a certain voltage threshold is exceeded. These components “wear out” with use and should be replaced periodically.

Mode – Mode 1 and Mode 2 are used by the Federal surge suppressor CID purchase specification. Mode 1 is the ground wire protection mode (no surge diversion to the ground wire). Mode 2 permits ground wire contamination, and is sometimes referred to as “all mode” suppression, or ground contamination mode.

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National Electrical Manufacturers Association (NEMA) – a forum for the standardization of electrical equipment, enabling consumers to select from a range of safe, effective, and compatible electrical products.

Neutral – One of the wires used in the USA to distribute power within a building. The neutral wire is generally connected to earth ground at a building service entrance, but unlike the ground wire, the neutral wire also carries load current.

Noise – An undesirable signal that is irregular and is riding on top of the desired signal.

Normal Mode Voltage – Voltage on the Line or Hot wire of the power wiring, compared to the neutral wire.

NRTL – Nationally Recognized Testing Laboratory, one example of which is Underwriters Laboratories, Inc. (UL).

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Oscilloscope – A measuring instrument which gives a visual display of voltage, current, or power waveforms.

Oscillogram – A picture of a voltage, current or power waveform taken from an oscilloscope.

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Peak Current – The maximum current value as measured from a reference in a given period of time.

Power (expressed in units of watts) – Power is the product of volts and amps. A circuit that will draw 1 ampere of current when 100 volts is applied will dissipate 100 (volts) X 1 (amp) = 100 watts.

Pulse – A pulse is generally a unipolar voltage or current with defined characteristics, which occurs infrequently.

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RFI – Radio Frequency Interference. High frequency interference that can appear on power wires.

Resistance – A property of electrical conductors or electrical insulators which characterizes their ability to conduct or resist the flow of electricity.

Ringwave – A low-energy test waveform specified by ANSI C-62.41-1991.

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SPD – Surge protection device.

SV – Suppressed Voltage, see Let-Through Voltage.

SVR – Suppressed Voltage Rating. A series of discrete voltages used by UL to designate the performance of a surge suppressor. 330 volts is the lowest (best), 400 volts is the next category, 500 volts is a third category. The SVR of a product to UL 1449 testing will likely be different from the SVR for the Adjunct Classification testing, since this UL 1449 Adjunct testing is at higher current levels, where the performance of a product may be different. When asking about SVR, be sure to specify whether the SVR is for UL 1449, or the UL 1449 Adjunct Classification testing.

Sacrificial – A term used to describe MOV based surge suppressors since they “wear out” with use.

Series Mode – Describes filter technology which opposes surge current and voltage while filtering off surges and noise, as opposed to shunt mode which diverts surge current and clamps surge voltage.

Service Life – The number of surges of given magnitude that can be suppressed by the suppressor, a measure of reliability. The Federal CID specifies minimum service life using a Grade A (best), Grade B, and Grade C classification method, with performance certified by a NRTL such as UL.

Shunt Mode – A form of surge suppression which diverts surge current and clamps surge voltage.

Sinewave – A fundamental waveform produced by periodic, regular oscillation that expresses the sine or cosine of a linear function of time and space or both.

Single Phase – The portion of a power source that represents only a single phase of the three phases that are often available.

Spike – See surge.

Surge – A brief burst of high level, high frequency voltage and current in an electrical circuit lasting for less than 1% of the power wave cycle duration.

Swell – A momentary voltage increase of the power voltage, lasting up to several seconds.

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TVSS – Transient Voltage Surge Suppressor.

Transient Attenuation – The reduction of a transient’s magnitude.

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UL – Underwriters Laboratories, Inc.

UL 1283 – Underwriters Laboratories safety testing standard for electromagnetic interference filters.

UL 1363 – Underwriters Laboratories safety testing standard for relocatable power taps.

UL 1449 – Underwriters Laboratories safety testing standard for MOV based surge protection devices.

UL 1449 Adjunct Classification – An optional performance and endurance test previously offered by Underwriters Laboratories. This was offered to manufacturers as an adjunct to their UL 1449 Safety Listing. Zero Surge’s technology was certified as Grade A, Class 1, Mode 1 – the highest U.S. Government’s classification.

Unipolar Pulse – A high energy test pulse specified by ANSI C62.41-1991. Also called a “combination pulse”.

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Voltage Protection Rating (VPR) – A key performance rating – essentially the “let-through voltage” during a surge.

Voltage Reference – A voltage point from which a measurement is taken.

Voltage Threshold – The voltage which causes the connected circuit to change its response.

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Watts – The unit of measure of actual power. Watts are the product of volts times current.

Waveform – The graphic form of an electrical voltage, current or power.

WVR – Wide Voltage Range. A filter technology that tracks powerline voltage over a very wide voltage range, maintaining effectiveness over that range.

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