Here are some of the terms that you may find on this site and throughout our marketing materials. If you need a deeper level of understanding, please do not hesitate to contact us by sending an email to

Alternating Current (AC)2021-04-01T12:18:12-04:00

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

Ampere (Amp)2021-05-18T09:27:36-04:00

Quantitative unit of measurement of electrical current. Abbreviated as amp or A. Devices are commonly rated by how many amps it requires for normal operations.

ANSI C62.41-19912021-04-01T12:19:55-04:00

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)2021-04-01T12:22:56-04:00

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.  They can sometimes be combined with Ground Fault Circuit Interrupters (GFCI) into one device.  AFCI’s have become required equipment in most locations of a building throughout North America. Check your local jurisdiction for the current requirements for your application.  Zero Surge technology does not interfere with the operation of AFCIs.


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


The Federal government, UL and other agencies establish standards of safety and performance. Testing labs such as Intertek can certify said performance, endurance, and safety meets certain standard safety levels.

Clamping Level (Clamping Onset Level)2021-04-02T07:26:02-04:00

This generally is used to describe the voltage level which causes a surge diversion device to start to divert surge energy. A related, but more important parameter is the Suppressed Voltage.  Zero Surge series mode filter technology is continuously filtering so there is no wait for the voltage levels to increase.

Clamping Time2021-04-02T07:27:15-04:00

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.  Zero Surge filters are always working so this feature has no meaning for our product.


Class 1, Class 2, Class 3

Let-through voltage, or Suppressed Voltage Rating (SVR) performance Classes defined by the Federal government CID in their power line 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.

Note – This standard is no longer used by the US Government but you may still see it listed as a property for surge protection.

Combination Pulse2021-04-02T07:48:14-04:00

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

Commercial Item Description (CID)2021-05-18T11:14:36-04:00

The Federal government develops CIDs for purchasing commercially available products. In 1996, they issued a CID for the purchase of power line surge suppressors with Grade A, Class 1, Mode 1 being the highest rating.

Common Mode Voltage2021-04-02T07:49:56-04:00

A voltage on the neutral wire of the power wiring, when compared to the ground wire, where the ground wire is assumed to be the reference.

Current (expressed in amperes or amps)2021-04-02T07:51:48-04:00

Current is the electrical flow of electrons. Current will flow in a circuit when the applied voltage exceeds a certain level, as dictated by the various components in the electrical circuit.

Flowing water in a hose is a good way to think of current flow.


Undesirable performance changes.

Direct Current (DC)2021-04-01T12:32:27-04:00

Electrical current which flows in one direction.


Undesirable disturbance.

Electro-Magnetic Interference (EMI)2021-04-02T08:09:02-04:00

Electrically induced noise or transients

Energy (expressed as joules or watt-seconds)2021-04-02T08:13:08-04:00

Property that is a measure of transferring work onto an object. There are many forms of energy. In electricity, energy is how much power is consumed over time.  The standard unit is joules which equals 1 watt-second.

For example: A 60 watt light bulb turned on for 1 second expends 60 joules of energy.

ETL Listed Mark2022-08-29T12:06:30-04:00

Proof that a product has been independently tested by Intertek and meets the applicable published North American safety standard.  ETL stands for “Edison Test Lab” – yes, that Edison!


A fault is a wiring problem such as a broken wire (open circuit), or wires touching (short circuit) typically due to storm damage, requiring physical repair.


An electronic device that allows only certain frequencies to pass.  Zero Surge uses a low pass filter which means that our filter allows low vibrating power to pass through unimpeded while stopping higher frequency vibrating power.  Unlike filters for liquids, electric filters that Zero Surge uses never needs to be replaced.


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).


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.

This standard is no longer being used by the US Government but you may find it referenced in our older literature.

Ground (Earth Ground)2021-04-02T11:53:30-04:00

For safety reasons (human and pets), 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”.  Receptacles were not required to carry a ground wire until the 1960’s.  Therefore you may live in an older home that does not have a ground wire attached to the receptacles.

Ground Contamination2021-04-02T11:54:26-04:00

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 (GFCI)2021-04-02T12:01:08-04:00

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.

Hertz (Hz)2021-04-02T11:55:56-04:00

Unit of measure of the frequency of alternating current. One cycle of oscillation is one Hertz.

IEEE 587-1980, ANSI C62.41-19912021-04-02T11:56:46-04:00

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.


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.


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 Equipment2021-04-02T11:59:04-04:00

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.  Or, a TV and cable box share an HDMI cable.

Internet of Things (IoT)2021-04-02T11:59:36-04:00

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 Termination2021-04-02T12:00:24-04:00

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.


A nationally recognized testing laboratory ensuring products meet quality, health, environmental, safety, and social accountability standards for virtually any market around the world.  Originally known as the Edison Test Lab (ETL), it is the oldest running independent test lab in the United States.

Joule Rating2021-05-18T11:30:38-04:00

Some protectors are rated in joules, meaning that if a surge exceeds the joule rating, the protector will likely be damaged. The joule rating of protectors reduces with each surge that the device encounters.  It is not an official safety rating of the product.  Zero Surge products do not have a Joule rating because our products do not degrade with use.  The amount of energy that our products can absorb is limited by the wiring in a building.  At some point the wire in the wall will break down before our product would and at that point the circuit is no longer powered.


A unit of energy, also known as watt-seconds.

Let-Through Voltage2021-04-03T20:31:46-04:00

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.

UL by rule will not issue a rating for less than 330 volts. Any device that has a let-through voltage of lower than 330 volts is listed as “<330 volts” which is what all Zero Surge products are rated.


An electrical device connected to a power source.  The “load” side of a circuit is where power is consumed.

Local Area Network (LAN)2021-04-03T20:32:29-04:00

An interconnection of computers, printers and other peripherals permitting the sharing of hardware and software resources.

Maximum Continuous Operating Voltage (MCOV)2021-05-18T11:32:52-04:00

This is the magnitude limit of continuously applied voltage.  This is a UL rated property of surge protectors.  If the voltage is maintained above this voltage, the protector will fail.  With Zero Surge Wide Voltage Range technology, the MCOV is 175 volts.  Most plug in surge protectors have an MCOV of <150 volts.

Metal Oxide Varistor (MOV)2021-04-03T20:37:22-04:00

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 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.

National Electrical Manufacturers Association (NEMA)2021-04-03T20:41:57-04:00

A forum for the standardization of electrical equipment, enabling consumers to select from a range of safe, effective, and compatible electrical products.  The cabinets that Zero Surge use for the Commercial Products line are rated by NEMA.

Nationally Recognized Testing Laboratory (NRTL)2021-04-03T20:46:32-04:00

This is a program that is run by the US Commerce Department which designates several laboratories as qualified to test for safety and performance of manufactured products.  Underwriters Laboratory (UL) and Intertek are two laboratories that Zero Surge has used for testing.


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.


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

Normal Mode Voltage2021-04-03T20:43:47-04:00

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


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


A measuring instrument which gives a visual display of voltage, current, or power wave forms.

Peak Current2021-04-03T20:48:31-04:00

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

Power (watts)2021-04-03T20:49:27-04:00

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.


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

Radio Frequency Interference (RFI)2021-05-18T11:45:51-04:00

High frequency (>500 kHz) interference that can appear on power wires.  The source of the interference is all of the communication transmitters around us from radio, TV, phones, Bluetooth, WiFi, etc. The wires that carry electricity act like antennae that can pick up the signals from these sources.


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

Ring Wave2021-04-03T20:54:56-04:00

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


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


A momentary voltage decrease of the power voltage, lasting several seconds or longer.

Series Mode2021-04-03T20:59:26-04:00

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 Life2021-05-18T11:48:51-04:00

The number of surges of given magnitude that can be suppressed by the protector, 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 nationally recognized testing laboratory (NRTL) such as Underwriters Laboratories (UL).

Shunt Mode2021-04-03T21:01:49-04:00

A form of surge suppression which diverts surge current and clamps surge voltage.  It is the most common method of surge protection in the industry.  However, Zero Surge does not use shunt mode technology since it can be unsafe and not very effective.

Sine Wave2021-04-03T21:02:23-04:00

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 Phase2021-04-03T21:04:52-04:00

The portion of a power source that represents only a single phase of the three phases that are often available.  Most of the electronics that Zero Surge protects use single phase power.


Surge Protection Device


See Surge

Suppressed Voltage (SV)2021-04-03T20:57:05-04:00

See Let-Through Voltage

Suppressed Voltage Rating (SVR)2021-05-18T11:53:27-04:00

A series of discrete voltages used by Underwriters Laboratories (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 the 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.


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.


A momentary voltage increase of the power voltage, lasting up to several seconds or longer.

Transient Attenuation2021-04-03T21:09:02-04:00

The reduction of a surge’s magnitude.

Transient Voltage Surge Suppressor (TVSS)2021-04-03T21:08:16-04:00

A synonym for surge protector.

UL 12832021-04-03T21:11:52-04:00

Underwriters Laboratories safety testing standard for electromagnetic interference filters.

UL 13632021-04-03T21:13:01-04:00

Underwriters Laboratories safety testing standard for relocatable power taps (devices with 3 or more receptacles).

UL 14492021-04-03T21:15:41-04:00

Underwriters Laboratories safety testing standard for MOV based surge protection devices.  More than 10 years ago, Zero Surge products were moved out of the UL1449 specification because so many of their safety tests did not apply to our technology because our products do not cause fires.  We have since been certified to the UL1283 and UL1363 (where applicable).

UL 1449 Adjunct Classification2021-04-03T21:17:01-04:00

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.  This testing is no longer offered because Zero Surge is the only technology that could survive it.

Underwriter’s Laboratory (UL)2021-04-03T21:10:56-04:00

One of the NRTL in the USA.  It has two separate units.  One creates and updates the UL standards.  One unit is their independent test laboratory.

Unipolar Pulse2021-04-03T21:17:46-04:00

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

Voltage Protection Rating (VPR)2021-04-03T21:19:35-04:00

A key performance rating – essentially the “let-through voltage” during a surge.  UL specifications require that the VPR is listed on the product.  The lowest rating by rule is stated as “<330 volts” which all of Zero Surge products meet.

Voltage Reference2021-04-03T21:20:08-04:00

A voltage point from which a measurement is taken.

Voltage Threshold2021-04-03T21:20:54-04:00

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


The standard unit of measure of electric power. Watts are the product of volts times amps.  Watts are also the product of Joules times seconds.

Wave Form2021-04-03T21:23:28-04:00

The graphic form of an electrical voltage, current or power over time.

Wide Voltage Range (WVR)2021-05-18T12:01:22-04:00

A filter technology that tracks power line voltage over a very wide voltage range, maintaining effectiveness over that range.  It is the standard technology for all Zero Surge products.

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