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Protectors Surge Protectors, UPS, Joules Explained SURGE PROTECTORS, UPS: Surge ProtectorsSurge ProtectionA standard surge protector passes the electrical current along from the outlet to a number of electrical and electronic devices plugged into the power strip. If the voltage from the outlet surges or spikes -- rises above the accepted level -- the surge protector diverts the extra electricity into the outlet's grounding wire. The surge protector should have an LED to indicate a good ground connection in your electrical wiring. Surge Protectors for home or office are designed to help defend against short voltage spikes which could be harmful to today's delicate electronic devices. Why do we need these surge protectors today? Why have we not needed them for the last 100 years? Because electronic devices today are designed to use very small voltages and current flows whereas devices of the past could largely ignore voltage spikes because they had no effect on the internals of these much larger devices which did not have any transistors, diodes or integrated circuits. In the home we have computers, printers, cameras, iPods, iPads, iPhones, flat-screen TVs, cable boxes, cable modems, home theater, audio/video receivers, Blu-ray/DVD players and other devices which are very sensitive to voltage levels. In the USA, electricity is available at around 110 to 120 volts at the wall outlets and also 220 to 240 volts for ovens, dryers and other larger appliances. Electronic devices which plug into wall outlets are designed to operate on 110 to 120 volts. A small flat-screen LCD TV for example operates at 120 volts, draws around 0.8 amps and peaks around 100 watts of power. In the United States, most homes use electrical power in the form of 120-volt, 60 Hz, single phase, alternating current. The voltage is not delivered at a constant 120-volts. With alternating current the voltage rises and falls in a rhythm. The voltage oscillates from 0 to a peak voltage of 169 volts. Using a digital multimeter at your wall outlet, you may see a reading of 122 volts for example which is available for your device. You are likely to never see the surges but your plugged in device will, and sometimes damage can be caused to your device. There are four main types of power disturbances: Voltage dips (also called sags or brownouts) Electromagnetic interference (EMI) Radio frequency interference (RFI) Power surges (also referred to as "voltage surges" or "transient voltages") Power surges are generally considered to be the most destructive of the four types of electrical power disturbances. Power surges are spikes in voltage. They are very brief, usually lasting millionths of a second. Power surges can vary in duration and magnitude, varying from a few hundred volts to several thousand volts. The reasons for spikes are many, including faulty wiring, problems with the utility company's equipment, and downed power lines. The system of transformers that bring electricity from a power generator to the outlets in our homes or offices is very complex. There are dozens of possible points of failure, and many potential errors that can cause an uneven power flow. In today's system of electricity distribution, power surges are an unavoidable occurrence. Power surges can originate inside a home when large appliances like air conditioners and refrigerator motors turn on and off. Power surges can enter a home through several paths. In the case of lightning, it can take the path of the cable TV or satellite dish coaxial cable, through the incoming telephone lines, or through the incoming electrical service line. A common cause of power surges, especially the most powerful ones, is lightning. There are over 20 million cloud-to-ground lightning strikes detected per year in the 48 contiguous states of the US. A major source of powerful electrical surge is lightning but lightning is in a class by itself as lightning can generate more than just a moment of marginal overflow. Even with a surge protector, grounding rods and other methods there are no assurances of protection with regard to lightning. There is no surge protection device or system that can protect against all power surges. A direct lightning strike to the house's electrical system may be too great for the surge protector(s) to handle. Even an indirect strike can be more than the system can handle. The best defense against lightning is to unplug your devices and also disconnect them from incoming signal cables. In other words, isolate the device from all connections. If you do not, you may find yourself buying a new device. Even though lightning strikes are rare for any given individual, it is better to be prepared than to lose your expensive electronics. If you leave your home for an extended period, such as vacation, always unplug and disconnect your expensive devices. Any cable coming into your home and going to your devices can carry a power surge, particularly from lightning. This includes telephone, cable TV, satellite TV, etc. connected to modem, fax, computer, HDTV, home entertainment and so on. Surges on these lines can do just as much damage as power lines. The surge protector plugs into the wall outlet and your electronic devices plug into the surge protector.  Surge Protector with eleven three prong outlets, coaxial cable, telephone and network ports. Some now even have USB ports. How does the surge protector actually work to protect your electronic gear? There are several methods used and some surge protectors even have multiple ways to help protect your devices. One method uses the MOV or metal oxide varistor. A varistor is a variable resistor. The metal is often zinc oxide. The varistor works by directing the voltage to ground when required.  The MOV can be smaller than a dime or larger than a quarter. The surge protector can have many MOVs for more protection. An MOV has three parts: the metal oxide material in the middle, connected to the power and the grounding line by two semiconductors. These semiconductors have a variable resistance that is dependent on voltage. When voltage is below a certain level, the electrons in the semiconductors flow in such a way as to create a very high resistance. When the voltage exceeds that level, the electrons behave differently, creating a much lower resistance. When the voltage is correct, an MOV does nothing. When voltage is too high, an MOV can conduct greater current to eliminate the excess voltage. In this way, the MOV only diverts the surge current to ground, while allowing the standard current to continue powering whatever devices are connected to the surge protector. Another common surge protection device is a gas discharge arrestor, or gas tube. These tubes do the same job as an MOV -- they divert the extra current from the hot line to the ground line. They do this by using an inert gas as the conductor between the two lines. When the voltage is at a certain level, the makeup of the gas is such that it is a poor conductor. When the voltage surges above that level, the electrical power is strong enough to ionize the gas, making it a very effective conductor. It passes on current to the ground line until the voltage reaches normal levels, and then becomes a poor conductor again. Some surge protectors also have a built-in fuse or a circuit breaker. A fuse is a resistor that can easily conduct current as long as the current is below a certain level. If the current increases above the acceptable level, the heat caused by the resistance burns the fuse, thereby cutting off the circuit. If the MOV doesn't stop the power surge, the extra current will burn the fuse, saving the connected machine. This fuse only works once, as it is destroyed in the process. A circuit breaker can be reset for another use. Which surge protector should I buy? Like many things, you get what you pay for and this generally holds true for surge protectors. At the low end, do not expect much from a $10 surge protector as it is usually made with inferior materials and will not protect your gear from large surges. These are mostly just power strips and have little or no surge protection. Moving up to the $20 to $30 range will provide better surge protection. Belkin has a very good offering of many surge protectors with a variety of features. Underwriters Laboratories (UL) ratings. UL is an independent, not-for-profit company that tests electric and electronic products for safety. If a protector doesn't have have a UL listing, it's probably junk; there's a good chance it doesn't have any protection components at all. If it does use MOVs, they may be of inferior quality. Cheaper MOVs can easily overheat, setting the entire surge protector on fire. Be sure that the product is listed as a transient voltage surge suppressor. This means that it meets the criteria for UL 1449, UL's minimum performance standard for surge suppressors. There are a lot of power strips listed by UL that have no surge protection components at all. Keep in mind that no surge protector is 100 per cent effective at all times. What to look for in a surge protector: Clamping voltage - This tells you what voltage will cause the MOVs to conduct electricity to the ground line. A lower clamping voltage indicates better protection. There are three levels of protection in the UL rating -- 330 V, 400 V and 500 V. Generally, a clamping voltage more than 400 V is too high. Energy absorption/dissipation - This rating, given in joules, tells you how much energy the surge protector can absorb before it fails. A higher number indicates greater protection. Look for a protector that is at least rated at 200 to 400 joules and preferably more, at 1800 to 2000 joules. Better protection at around 3200 to 3500 joules increases your cost but may save your devices. See: What is a joule below. Response time - Surge protectors don't kick in immediately; there is a very slight delay as they respond to the power surge. A longer response time tells you that your computer (or other equipment) will be exposed to the surge for a greater amount of time. Look for a surge protector that responds in less than one nanosecond. Indicator Light: You should look for a surge protector with an indicator light that tells you if the protection components are functioning. All MOVs will burn out after repeated power surges, but the surge protector will still function as a power strip. Without an indicator light, you have no way of knowing if your surge protector is still functioning properly. Your Surge Protectors should have a red LED surge status indicator so you can always be sure your unit is protecting your sensitive electronic equipment. Performance Guarantee: Quality surge protectors usually come with a guarantee of their performance. Look for those that come with some form of Connected Equipment Warranty. This way, if the surge protector fails to protect your equipment from a harmful surge, the company will actually replace it. In contrast, a Manufacturer's Warranty warrants only the surge protector to be free from defect and will therefore only replace the surge protection unit - not your damaged equipment. Your Surge Protectors should come with Limited Connected Equipment Warranty's ranging from $200,000-$500,000 to cover losses to your connected equipment. Always keep your original sales receipt for all your equipment as the warranty company will ask for these details as proof of purchase. Connectivity: Many damaging power surges enter through information lines, including your phone, DSL or cable connection, rather than power lines. These dangerous power surges or spikes can ruin your phone system, answering machine, computer, game console, cable box, VCR, Tivo or HDTV. Some surge protectors offer protection for these types of information lines via additional connectors such as RJ-11, RJ-45 or coaxial cable connections. EMI/RFI Filters: Electromagnetic Interference (EMI) in the electrical current has been shown to hurt equipment performance and be a source of errors. Additionally, this form of interference can also cause damage to sensitive components over time. Radio Frequency Interference (RFI) can cause distortion or hissing in audio playback and streaming. What is a Joule? a joule (pronounced like jewel, ie. diamonds, emeralds) is a unit of energy named after James Joule, an English physicist who lived from 1818 to 1889. A person at rest expends about 100 joules of heat energy every second. joules = watts × seconds. So a 60 watt bulb on for 30 secs = 1,800j 1800 watts for 1 second = 1800 joules watts = volts times amps 1 BTU = 1055 joules One BTU is the amount of energy needed to heat one pound of water one degree Fahrenheit. MOVs are rated by the number of joules they can absorb, which is a finite number. Ultimately, after the MOVs absorb all of the joules that they can, the surge protector will activate its cut-out circuit and sacrifice itself for the benefit of the connected equipment. Question: When I run my coaxial TV cable through the surge protector, I get dropouts, pixelation and even some digital channels are completely gone. What causes this? Answer: Unfortunately this is a known problem with some surge protectors. Cable TV technicians will tell you to not run your coaxial cable through the surge protector, particularly when using digital cable channels. One solution is to connect an in-line surge suppressor at the point where the coax cable first enters your home in addition to a surge protector at the point of use. • When in doubt, SEE if your remote control is working • In-wall wiring speakers, cables, home theater, CL2, CL3 • • Satellite TV home installation guide • DVR - Digital Video Recorder • DVD Recorder Buying Guide • HDTV Buying Guide • How to hook up a cable TV box • How to hook up a SA4250HDC digital cable TV box • How to ground your coax cable and TV antenna - Lightning Protection • Broadcast TV reception • Insignia ns-dxa1 - TV converter box for digital TV on your old analog TV set • Surround Sound • Switch boxes video audio RCA phono and more • Audio Video selector switches including Toslink • All About HDMI - HDMI Cables • SiteMap Surge Protectors Surge Protection Terminology Surge protection and the associated protection devices on the market can be confusing to a homeowner. Here are some definitions which may help to understand the terminology. Surge Protection Devices have several names: surge protectors, surge suppressors, transient voltage surge suppressors (TVSS), or secondary surge arresters. But they essentially have the same function of protecting against power surges. Surge Protector: These devices are designed to protect equipment "downstream" against power surges by reducing the amount of voltage they let through. Many electric utility companies also use secondary surge arresters and devices called lightning arresters throughout their electrical grid to protect their equipment from lightning damage. The devices they use are more durable, but can't reduce the power surge down to the lower voltage levels that in-home products can. Secondary Surge Arrester: These devices are designed to go on the inside or outside of the house. If tested, they are tested according to the recommendations of the Institute of Electrical and Electronics Engineers (IEEE) standard C62.11, Metal Oxide Surge Arresters for Alternating Current Power Circuits, with a 10,000-volt, 5,000-amp power surge. These devices include the meter-mount surge protectors and the plug-on surge protectors that snap into the electrical panel. Transient Voltage Surge Suppressor: TVSSs are generally designed to go on the inside of the house. If tested, they are tested according to Underwriters Laboratory (UL) standard UL 1449 with a 6,000-volt, 500-amp power surge. UL 1449 assigns a clamping voltage to the TVSS which can be used for comparison from one product to the next. These devices include the point-of-use surge protectors and service entrance surge protectors mounted on the electrical panel. Clamping Voltage: TVSSs should have a clamping voltage specified. Clamping voltage is the voltage at which a surge protector begins to work by redirecting the power surge to ground. The lower the clamping voltage of the surge protector, the lower it will reduce the power surge voltage. UL 1449 2nd Edition: This is a test standard that was developed by UL in conjunction with industry to certify product ratings and ensure proper markings on TVSS products. Through this test, the clamping voltage is determined. IEEE C62.11: This standard, written by the Institute of Electrical and Electronics Engineers, has recommendations on how to test secondary surge arresters. [IEEE C62.11: Standard for Metal-Oxide Surge Arresters for AC Power Circuits (>1 kV)] Let-Through Voltage: This is the residual surge voltage that passes through a surge protector after the protector has "clamped" in response to the power surge. The clamping voltage does not determine the level of let-through voltage for all power surges. For example, if a point-of-use surge protection device has a clamping voltage of 330-volts, that means the device will let-through no more than 330-volts if the power surge is exactly the size, shape and duration of the 6,000-volt surge required in the test standard, UL 1449. If the same device (with a 330-volt clamping rating) is subjected to a power surge with a higher energy level (voltage, amperage, or duration), the let-through voltage will most likely be above 330-volts. Metal Oxide Varistors (MOVs): MOVs are a common technology (not the only type) and are at the heart of the surge protector's (TVSSs) ability to protect against power surges. Generally, the larger they are and the more there are equates to better protection and a more durable, longer-lasting surge protection device. MOVs redirect the electrical current in the event of a power surge. How an MOV works is easier to understand if you think of it as a water spigot. Under normal conditions, without power surges, the MOV is a "closed valve" allowing current to flow in the electrical circuit and not through the MOV. If there is a power surge, the MOV clamps the voltage by redirecting the electrical current (opening the valve) from the electrical circuit into the grounding system until the surge voltage drops below the clamping voltage of the protective device. When the power surge is over, the MOV returns to the "closed-valve" position. During the power surge, all of the excess energy of the surge is diverted by the MOV, causing it to get hot. The temperature of an MOV disc can vary from room temperature to several hundred degrees after a power surge has been redirected. The higher the voltage of the power surge, and the longer it lasts, the more energy that must be diverted and the hotter the MOV becomes. MOVs are sacrificial, meaning they will divert a finite number of power surges until they are eventually destroyed. They may reach end-of-life after only a single large surge or over several years from several smaller surges. Thermal Fuse Protection: Because MOVs heat up when handling a power surge, there is a potential for the surge protection device or material surrounding the surge protection device to catch fire. The 2nd Edition of UL 1449 tests the fire safety of the TVSS surge protection devices by requiring severe overvoltage tests, causing the MOVs to fail. The surge protection device passes if it does not create a fire or electrocution hazard. This is commonly accomplished by the use of thermal fuse protection. Under the previous version of UL 1449 surge conditions could cause the surge protector to overheat and catch fire. The thermal fuse reduces that risk. L-N, L-G, & N-G Protection: The electrical system in your home is typically a three-wire system. The wires are the ground, line (hot), and neutral. A power surge can exist across any of these wires. The surge protection should protect against surges coming through any of these wires. When a surge protection device indicates the following, you know all wires are protected: Line to Neutral (L-N), Line to Ground (L-G), and Neutral to Ground (N-G). Secondary surge arresters installed at the service entrance have only Line to Neutral (L-N) protection because there is no ground wire in the locations where they are installed. surge suppression The diverting and/or diminishing of excessive current and voltage from the AC power line, which can damage sensitive electronic equipment. Power surges generally last less than 50 microseconds, but can reach as much as 6,000 volts and draw 3,000 amps when they arrive at the equipment. There are two principal types of technologies used in surge protection devices. Shunt Mode - Divert The most common method is the use of a metal oxide varistor (MOV), which acts like a pressure relief valve to divert the surge to the neutral and/or ground lines. However, shunt mode methods can be problematic. Diverting high voltage to ground may damage equipment because all electronic devices are interconnected via ground. Since all data lines use ground as a signal reference, excessive voltage on that line can disrupt and impair networks and communications. In addition, MOVs can eventually stop working without warning. There are countless low-energy surges occurring all the time, even from innocuous, everyday operations such as turning a motor on and off. Each surge causes a minuscule degradation in the MOV. If the MOV is high quality, it can take decades before the countless surges render the MOV ineffective. In a poorly made device, they can add up to failure in a much shorter time. Series Mode - Block and Absorb Series mode surge protectors actually block high current and absorb excessive voltage. They do not divert current to ground, but limit the surge to acceptable levels that electronic equipment can handle. Another feature of series mode is the ability to suppress all excessive voltage rather than wait for a certain level. MOVs shunt the current when a preset voltage is reached, but series mode units can track the powerline voltage and activate the suppression components as soon as the voltage goes over the norm. Zero Surge, Inc., Frenchtown, NJ (www.zerosurge.com) is the pioneer in series mode technologies and began shipping their products in 1989. Hybrids Surge protectors may use both shunt mode and series mode methods in some combination. For example, they may use series mode for low-energy surges and shunt mode for high-energy surges. 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You also need to know how to select the proper input on your components and how to setup on-screen menu options and other audio/video knowledge. |