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TVSS SURGE PROTECTION Maybe more than you want to know.
She went out yesterday and bought a BELKIN "SurgeMaster" surge protector that protects to the tune of around 2655 joules. It has six outlets, one phone line "in" and two "outs." This protection device has an indicator light that is supposed to shine when grounding is present. Instead, the light flickers briefly and then goes off. The guarantee on the product implies that the consumer is entitled to up to $250,000 in damage insurance if the device is used on a grounded circuit. My questions are these: What is a safe amount of protection (in joules) for your home appliances and how does anyone know for sure (given the variations possible when you're dealing with lightning) what a safe amount of protection would be? Would this "SurgeMaster" device provide a reliable means to test grounding, and if it is reading correctly, does that mean the outlet is not grounded? Finally, if someone does have to come out and run ground for the outlet, isn't it possible to install surge protection at the service to protect the electrical equipment? Mike Smith Response No. 1: 2. While the "SurgeMaster" device is not a ground tester, if the ground light is not on, that would indicate that either there is no ground to that receptacle, or the ground wire has not been connected or is loose. Either way, the surge device at that receptacle will be of little service. There is nowhere for the device to shunt the surge energy. 3. The most efficient and effective way to deal with surge events (especially at a residential site) is treating them before they enter the home. Your concept to install a quality surge device at the service entrance to the house is perfect. But, remember the phones and cable/satellite, not only the entrance of the power. 4. The surge device to protect against
surges over the power lines should be: 5. For any surge device to work effectively, the ground system has to be in good shape. Your idea to install the ground at the entrance and protect it there is perfect. Install two ground rods, one very close to the service entrance, the other rod 20 ft away (assuming 10 ft rods). Dig a trench 20 in. deep by 24 in. wide and bond the two rods together with copper conductor, and then cover the conductor in a ground enhancement product (like Conducrete). Make sure the ground rods are driven to at least 6 in. below grade. Replace the removed dirt over the enhancement material, and you're done. 6. For diagrams and specific device
recommendations please feel free to contact me directly or visit these Websites: www.cutler-hammer.com
and www.saeinc.com.
1. Does it have a "grounding ring" around the outside, preferably #2 copper laid at one or two inches in the footings (perimeter) and bonded to the incoming water pipe? Is it bonded to the incoming transformer conduit, and also bonded to grounding rods 10 ft deep and other metallic members? 2. Surge protection is fine on the main lines and also supplement ones. I don't think any amount of joules can really protect 100 percent but the higher the energy level, the better protection you should receive, even though not at the 100 percent level - maybe 90 to 98 percent. I also get the feeling from the STMT that the light comes on briefly and then goes out. Am I interpreting that to mean that there may be some "grounding" bonding on that green wire, maybe with a higher than three percent resistance, or greater than 5 ohms. I need to know more and ask more questions. Refer your member to "Soars Ground
Book for 2002." Response No. 4: Lightning typically is not a direct hit. If it is, there isn't much you can really do to protect against that kind of energy, short of living in a Sherman tank. The more likely occurrences are induction into the power lines, and phone lines caused by capacitive coupling and collapsing magnetic fields. The energy induced into the line is exponentially proportional to the distance away. Hits as far away as 12 miles can still cause elevated voltages; hits within 1/4 mile can cause severe damage. There are several standards to represent the current stroke induced on a line. IEEE started out with the 8/20 us (microseconds) waveform. This means the stroke wave rises from 0 to max value in 8 us, and falls to 50 percent of nominal value in another 20 us. American manufacturers loved this standard because with a pulse this short, they were able to publish extremely high- energy numbers. What was found was that many of the devices would fail when used because the energy pulse, in reality, was longer than that theorized. The Europeans pushed for a 10/1000 us waveform. You generally don't see that published much in the U.S. because it takes energy numbers like 1250 joules and makes them 125 joules. So, to really know the energy rating of your productor,*(?) you have to know the waveform it represents, or you need to know its continuous energy rating, which might be something like 0.5 joules, and from there you can form some educated guesses. Protectors also come in different formats. They can be series wired or parallel wired. Series devices generally use inductors. Inductors are great because at normal AC frequencies of 60 Hz, they have little impedance, but at a lightning stroke frequency of 200k Hz, the impedance is huge, and hence provide attenuation of the strike peak levels. Most of the main panel units are going to be a parallel device. For a house it would be four wires, two hots to a 2-pole branch breaker, one neutral, one ground. To improve performance, cut the wires as short as possible, and make the ground as low an ohmic value as possible. Do not mount the protector leads under the main, as the protector must have short-circuit protection. Most of these units use Metal Oxide Varistors (MOVs), which often fail as a short circuit and can cause a lot of "follow-on current." The protector you described sounds like it is a series device, which you can accomplish more easily on low-current lines. I say it is a series device because it claims to have a filter with attenuation of 45 dB, although it doesn't say at what frequency. It probably is at 1 MHz, which is a frequency used often because a small inductor produces a big attenuation number at this frequency, but if you checked at 200k Hz, it may only be 3 or 6 dB. Everything with lightning is probability. The device you bought is probably of sufficient quality and design for 98 percent of occurrences. Since it has a filter, it sounds like one of the better ones. My guess is that it is still MOV based and these devices do not provide flat responses. The MOV is similar to a zener diode in that it doesn't conduct unless there is a sufficient voltage differential across it. They often use 150V MOVs on 120 ac devices. But the response curve is not flat, and as current through the MOV increases, so does the voltage across it. So to get rated energy values, the voltage on the line may need to reach 300V. Will that level damage sensitive equipment? It might. There is a lot to know about this subject. But if you really want to "protect" your lady's house, I would tell you to keep the line protector you just bought, but look to add a main panel protector also. There is a lot of money being made in surge protectors. The manufacturer's trick is to advertise big current and energy handling numbers, and put the least amount of components in the package. The consumers' job is to find the most value for the money. The problem is that you need to be very knowledgeable to know the difference. Below are a couple of Websites that sell products. For the house, I think the delta product
may be sufficient. It is priced right, and without talking to the manufacturer to verify
ratings, it gives you a combination of a large capacitor and MOV package. Let-through
voltage may be higher than some others, but it may be more survivable, and sufficient
if you have secondary protectors. I am not selling them, nor have I bought any, it's just
an observation. There are some good units on the market that are industrial quality but
they start at about $600 each. So if she is only your girlfriend, go for the $108 combo
package. Save the $600 protectors for your mistress.
But the real thing is this - you must
have a good ground. I would replace the one you purchased with another because of the
blinking ground lamp. A simple test of the grounded outlet can be made with a multimeter,
or buy a three-prong GFCI tester from a good hardware store (about $10) and test the outlet.
This will also detect a hot/neutral reversal. You can use this tester in all outlets in
the house for years to come. Next, it is very important to keep all incoming services on the same ground plane (electrical, TV coaxial cables, telephones, dish, etc.). Thus the reason that the electronic device, such as a computer and data circuit (telephone modem, DSL, cable modem), be protected at the same outlet with a SPD with those hookups. Another important issue - all incoming services I mentioned above must be at the same ground plane outside the building, house, apartment, etc. The NEC requires that the grounding electrode for the electrical main service, telephone ground at the Network Interface Device (NID), coaxial TV cable ground be referenced together (bonded). This is normally done outside the building. Now all incoming cables, power and telephone etc., are at the same ground plane outside the house. In theory, any surge seeking ground will not travel through the house from one ground plane to another, destroying stuff on the way. It instead will remain outside and disperses in the surrounding earth through low-impedance and intentional grounded paths. Some residual current may enter the house (parallel path) but the impedance offered by the small house wiring (14 to 12 AWG) will lower the remaining potential surge and allow the Class "A" SPD to safely control any remaining currents. My advice is to purchase an American-made
SPD. There are many companies that offer a variety of SPDs for the home and industry.
While I am not pushing any one brand, I suggest these Websites: Joslynsurge.com, citelprotection.com,
or Panamax.com. Whatever brand you buy, make sure it has an official UL label on the device
itself, not just on the cord. Go to www.safetyalerts.com
and look under Electrical, then to Surge Protectors for recalled items. Most are made
in China and may be a fire or shock hazard in your home right now.
Other surge suppressors rely on "sacrificial
components," Metal Oxide Varistors (MOVs) or gas discharge devices that shunt or
divert power surges from the hot line to the neutral or ground line. Sensitive digital
equipment systems depend on a clean and uncontaminated ground. Response No. 7: In order to answer these questions, one must discern between four different types of lightning damage to electrical equipment. Three (ground surge, conduction through power lines, and direct strike) can be generally categorized as power surge damage; in all cases, the Electromotive Force (EMF) of the strike's potential breaches insulation in electrical devices and causes damage. The fourth, generally known as inductive coupling, causes over 80 percent of lightning damage to electronics. It's caused by an Electromagnetic Pulse (EMP) from the strike, which in turn generates a voltage on long cables within approximately 1/4 mile of the strike's location. Although inductive coupling generates very little power, the voltages can be on the order of 30,000V or more, depending on the orientation and length of the cable and its proximity to the strike. All the damage described in this case (telephone, answering machine and computer) is extremely typical of inductive coupling; the coupled surge entered through the telephone lines connected to each device. With respect to guarding against inductive coupling damage in electronic equipment, anything is better than nothing, but the point of diminishing returns comes fairly early for home electronics. The important thing to look for in choosing surge protection is not how many joules the protective device will absorb, but how quickly it will react and how accurately it will clamp. For instance, if a device is supposed to protect a telephone line, then a clamping voltage of 150 VDC is useless. Similarly, if the device takes more than .1 seconds to clamp, the damage is done; the surge protector may still take damage, but its sacrifice is wasted. Therefore, if you really want peace of mind regarding the efficacy of a surge protector, it's important to know what it's designed to protect against. Inductive coupling protection is best accomplished by diodes; surge protection is best accomplished by devices such as Metal Oxide Varistors (MOVs), which are slower but have a much greater ability to absorb power and recover from surges. Combinations of these approaches have also proven useful, assuming the devices are properly designed and the home's grounding is sound. Unfortunately, manufacturers of surge protection devices are rarely willing to discuss the functional details of their products with the general public. Therefore, my general advice is to make sure that the grounding in your home is good, pick most any device that will support every line connected to the appliance you're trying to protect, and forget about it. Barring that, simply unplug every phone line in the house whenever there's a storm in the area. "Would this "SurgeMaster" device provide a reliable means to test grounding, and if it is reading correctly, does that mean the outlet is not grounded?" The answer is no and no. "Finally, if someone does have to come out and run ground for the outlet, isn't it possible to install surge protection at the service to protect the electrical equipment?" It is, but again, this only protects the line side; most damage to electronics comes from inductive coupling through communication cables. Just for reference, my own personal
computer uses no protection on the cable modem, and an ancient UPS for protection of the
power circuit. In eight years and four different houses, I've never had lightning damage
to my computer (and we get a lot of lightning in NC).
These devices work well to limit damage but as for my past experiences, some occurrences get by and do damage. Don't tell me anyone can stop a direct hit by lightning. It's like trying to stop a freight train. You might slow it way down and save some damage, but you're not going to get it stopped completely no matter how many degrees you have hanging on your office wall. I personally use these devices on my
own equipment, both communication and power, and highly recommend that name brand equipment
be used. It will greatly limit damage, but don't expect to stop that FREIGHT TRAIN.
1.Meter Based Arresters. Mousa points out that the field carried
by the tip of the lightning leader is a zone of 800 to 1,000 kV/m... AND it is an invalid
claim with respect to lightning dissipators that, on a large scale, can eliminate the
effects of lightning.
A general rule of thumb is you get what you pay for in surge protection, and name brands that have a history of good products are a better way to go. None of the manufacturers can build a device that will protect against all lighting strikes because there is no way of knowing how "big" the hit will be. Thus, it comes down to this - if you get a direct or nearly direct hit, it wasn't your lucky day no matter what you install. There is however a study that I think puts some light on the subject done by Progress Energy (formerly Florida Power). On July 15, 2000, there was a major storm in the Tampa Bay area that generated 33,863 cloud-to-earth lightning strokes. Of the positive strokes, 95 percent were less than 30 kA and 98 percent were less than 60 kA. Of the negative strokes, 82 percent were less than 30 kA and 98 percent were less than 60 kA. Thus about two percent of all lighting strokes would be over 60 kA. If you then consider what is feasible in regard to the service entrance to pass the surge into the building without getting blown to pieces, you can come up with a degree of protection that is reasonable. Two levels of protection seem to be the most suggested protection, the first at the main panel and the second at the point-of-use. One should keep in mind that MOST of the surge-related problems happen INSIDE a building and are not related to lightning. Lightning is just a huge surge when it happens so it gets more attention. Relate this to a plane wreck vs. a car wreck. A presentation by the Square D factory in Cedar Rapids, Iowa provided much of the above information as well as some of their results on testing surge-related devices. Square D has available an Engineering Manual in both book form and CD that address surge protection. Several other manufacturers also have provided information to me. One even pointed out that in a shopping adventure that they conducted as to the quality of products on the shelf available to the general public, one product was UL listed on the package BUT, it was the package NOT the surge strip, which was nothing more than a multioutlet strip. I have seen packages that say the product will protect against lightning only to say on the back of the package that it doesn't (in smaller print). I assume this is because of the unknown size of any given strike. An effective grounding system is critical for the successful operation of any surge-protection device. Given that an older home is in question, I'd have the grounding system checked out and upgraded to current standards. Since the surge device indicator light goes out, I'd think it was either defective or there isn't an effective ground present. One other point is that surge-protection devices don't last forever. The life of any surge-protection device is directly dependent on the type and size of surges it has to deal with. So, an indicator built into the device is a worthy option. Some devices provide a light, others an alarm or both. The alarm is preferred in most cases where the device is installed in a hidden location such as under a desk. Remote alarm systems are also available. One other point, surges have always been here, it is just that our products that we now use are more sensitive to them. Computers and home entertainment systems are most often pointed out. However, think about any product that uses electronics in controls. Our gas stove has a very expensive processor board the makes the thing work. There is a surge-protection outlet it is plugged into that is much cheaper than the processor board to replace. READ the product guarantee carefully.
There are many times other requirements that must be met to collect the insurance.
I don't think any amount of surge protection in the wiring will prevent damage to a highly sensitive computer or other sensitive electronic equipment from a direct hit on a house by lightning. Surge protectors are designed to protect from power surges and spikes in the wiring, not lightning strikes. A surge suppressor that comes with a $250,000 guarantee to fix the equipment if damaged by lightning, is mostly an insurance policy. Read the "guarantee" carefully, and make sure that the "loopholes" do not make it almost impossible to collect. Some power companies offer a "protection policy." If your equipment is damaged by a power surge from their power lines, they will fix or replace things, usually under $5 per month. For under $5, you can get a tester from Home Depot or Lowe's that just plugs into the outlet, and tests for ground, and for wires connected wrong. It will not test the QUALITY of the ground connection or the QUALITY of any of the connections. Hire a really good electrician for that. 2. She went out yesterday and bought a BELKIN "SurgeMaster" surge protector that protects to the tune of around 2655 joules. It has six outlets, one phone line "in" and two "outs." This protection device has an indicator light that is supposed to shine when grounding is present. Instead, the light flickers briefly and then goes off. That is an F9M Surge Suppressor, series. Indicator lights should always flicker on first, to show that the light has not burned out. Otherwise, my wife might think, "Oh, the light is just burnt out, I know my ground is good, see, there is a hole in the receptacle for ground." Here is a quote from the Belkin Instructions: "The 'Protected' light should be on when the power is on. If this light goes out at any time, that means your surge suppressor was sacrificed to protect your equipment and should be replaced in order to save your equipment. Please contact Belkin for a free replacement surge protector in this case. The 'Grounded' light should be on when the power switch is turned on. If this light does not come on when you plug in your Belkin surge protector, you should contact an electrician to properly ground the outlet." It also says they will give you a new surge protector free if the problem is in the ground light. And they will void the warranty if you use a nongrounded outlet, a very big and valid loophole in their warranty. My advice, since the "Ground light" indicates a problem with the ground: (a) Have a really good electrician check out the outlet, and fix the outlet so the ground connection is good and safe. When a ground is bad, the danger is to you and your family. I don't care about the computer or the surge suppressor. (b) As long as he is there (since your
house was struck by lightning), have a really good electrician check out the entire house
wiring and electrical outlets. Hey, I am cheap, why pay for two service calls!
In short, the factors to consider include
risk and cost. Unfortunately, the risk of lightning is poorly quantifiable, and thus its
estimation might be a better indicator of the emotion of you and your significant other
than of the real physics of the situation. At least consider as a general point the proximity
that the lightning strike affects, and which means of protection are most effective. Additionally,
consider that a direct strike to certain parts of the building itself cannot be reasonably
protected against with certainty.
If the houses were to be updated to
have a 20 megohm reading resistance for the ground, this should not happen.
Having a surge protector for CATV and
phone lines is critical. People don't understand that power supplies are fairly robust
with their own internal surge protection and capacitors, which can absorb a fair amount
of energy. However, the low-voltage lines are connected directly to the circuit board,
so the only way to protect from surges coming in from phone and CATV lines (or their being
at ground potential when a "surge" comes in from the power lines) is to have
them clamped to the same potential as the power cord at the surge protector. Having a
surge protector with an effective ground on the main panel also helps.
2. The ground indication appears to be showing that the ground connection at the receptacle is of fairly high resistance or that the surge protector is faulty. One test would be to plug it into another receptacle to determine if the unit is bad or there is a problem with the receptacle. It's very important to have a good ground connection in order to provide full protection. 3. Surge protection at the incoming
panel is a good way to provide protection from power-line surges. But, the computer equipment
still will need a good ground. And, you need to provide surge protection on your telephone
lines and/or DSL line. Best advice would be to ensure that a good ground is established
at the computer receptacle.
1. Joules are probably the most over-marketed and least understood specification. When surge suppressors are tested by UL (or other listing agencies), one of the test pulses used consists of 6,000V, 500A, and lasts for ~30 microseconds (ANSI C62.41). This pulse is used to simulate a lightning strike entering from the utility lines and coming through the service entrance. This works out to about 90 joules. If, on the other hand, you had an overvoltage of 180V, 100A that lasted for half a second, you'd have 9000 joules. So, for fast transient surges (like lightning), it looks like the Belkin unit should be able to handle it. Longer duration overvoltages may be another story, though. 2. The outlet diagnostics in a surge suppressor are generally not as good as a dedicated device (Sure Test, etc.). When using a surge suppressor to check outlets, make sure that there is nothing else plugged into it (AC, coax, etc.) as this can cause false readings. If a surge suppressor is showing that there is a line fault, it could mean that there is no (or bad) ground connection, that the line and neutral are reversed, or that there is excessive noise (EMI, RFI) on the line. 3. Service Entrance Protectors (erroneously
called 'whole house protectors') are great for 'white goods' items (refrigerators, motor-driven
appliances, etc.), but are not adequate for devices like TVs, computers, etc. Using a
service-entrance protector along with plug-in protectors makes for a great one-two punch
to knock down surges. Response No. 30:
1. Joules - There has been an ongoing debate with respect to joules and product performance. I hope to convey what benefits are gained by higher joules and, as such, dispel any myths that may have been perpetuated through the surge Industry. MOV Ratings - MOVs are rated by six
typical areas of performance. They are: Nominal Voltage @ 1 mA DC (Vn) - This is the "Knee" of the MOV, the voltage that the MOV will conduct with 1 mA of current. This Knee is more of a correlation to the clamping voltage. Maximum Continuous Operating Voltage (MCOV) - This is the maximum AC voltage that the MOV is rated to operate at and not conduct. It correlates to the Vn as defined above. Maximum Surge Withstand - Maximum surge level, typically an 8/20 uS current level that the MOV can clamp without suffering serious degradation. It correlates to joules, disk diameter, and the area that is covered on the disk by the lead that contacts the disk. MOV Disk Diameter - This is in direct correlation to joules; the larger the disk diameter the more joules it will be rated for, and as such its maximum surge withstand would be higher. Typically, most standard 20mm disks are rated for 6.5 kA and the newer super MOVs are rated at 10 kA. Maximum Surge Life - The number of surges that a MOV can take at a specified surge level (typically 3 kA) before the MOV's "Knee" starts to degrade. This is directly related to joules. Studies: Parallel MOVs - I have also tested and sorted MOVs that were paralleled, which would give higher joules but have reduced the clamping voltage. This is not because of the joules being higher, but because there is current sharing between the MOVs and the current is now split from 500A for one MOV to be approximately 125A per MOV when four MOVs are paralleled. From maximum surge tests I have performed, the maximum surge withstand is increased with the higher joule rating (example, Panasonic's older 20mm "C" Series MOVs were rated at 6.5 kA and their newer 20mm "V" Series "SuperMOV" are rated for 8 KA. The "C" MOVs had a lower joules rating than the currently offered "V" MOVs, and their effective clamping voltage was equal. However, on a side note, a MOV that has a higher joule rating and a higher Knee has the same maximum surge withstand rating as a MOV with a lower Knee and lower joules. From surge life tests I have performed, the higher joules increase the maximum surge life. Does Higher the Joules Equal the Better the Product? From my studies and knowledge of MOVs, the answer is "well, kind of, but" - the product itself may have other weaknesses such as the internal wires, fuses, circuit breaker and printed circuit board that may not be able to sustain that high of an energy-rated surge and, as such, would lessen its maximum surge withstand. The maximum surge life would be higher and is dependent again on internal components being able to withstand repetitive surges. A MOV's clamping or let-thru voltage is dependent on its Vn at 1 mA, and how many are in parallel. I can use a MOV that has a higher Knee and MCOV, such as a 300 VAC MOV where we would normally use a 130 VAC MOV and get a much higher joule rating, but my clamping voltage would be increased from 330 to 800V or +242% HIGHER!! My surge life would not change and my maximum surge withstand would not change. Summation: 2. Ground Detection - Belkin has a reliable ground detection circuit and if the light fails, then have the outlet inspected for proper grounding and have the service panel checked for proper ground bonding. 3. Service Entrance - I am a strong
believer in panel protection; however, that only protects the building from external surges.
It does not protect from internal surges, so the user should deploy "whole house
protection," which entails a panel protector at the service entrance and a surge
strip protecting each outlet that has sensitive equipment (computers, A/V equipment, and
the like), Telco protection for every phone, Fax and modem connect, CAT5 protection at
every network connect point, and CATV protection for cable modem, TV, VCR, and the like.
First, it appears that all of the equipment affected was associated with the phone system. It is very likely that the phone ground is not connected or bonded to the electrical ground system. The difference of potential caused by the lightning strike was most likely felt at the electronic devices that failed. (I would check the modem in the computer for failure also). I am not sure of the actual joule requirements for safe protection, but the 2655 joules mentioned should be sufficient. The main problem is that no amount of surge protection will work if proper grounding is not present at the point of protection. With the statement of this being an older home, the existence of proper grounding is questionable. A quick check would be the existence of three wires at the outlet in question. Surge protection can be installed at the main service panel and, in fact, is a good idea. This would help in reducing the surge potential entering the house. This protection should not be the only device used. A surge-protection device (surge strip) should also be installed on each and every sensitive electronic device especially where more than one utility service is being used by the device, such as the computer (phone, electric, cable), answering machine (phone, electric), some phones (electric, phone). I hope this answers some of the questions
that were being raised.
Joule rating - This is a very controversial method of rating Surge-Protective Devices, or SPDs. A joule rating refers to the amount of energy a Metal Oxide Varistor (MOV) can absorb. One joule per second is equal to 1W, a unit of electrical power, 746 watts = 1 hp, etc. So, by this theory one would think that the higher the joule rating, the better the SPD, right? - Wrong! There is a connection, but the most important aspect of the SPD is installation (more on this later) and the Let-Through Voltage (LTV). The lower the LTV, the better, as this is the voltage or remnant of the spike that will travel to your expensive electronics. The primary components of SPDs are MOVs. MOVs have a MCOV value (Maximum Continuous Voltage Rating), or turn-on value. This means that once this surge reaches this "turn-on" level, the MOV will start to conduct and shunt the surge to ground. For a 120/208Vsystem, MCOV values could be 150V or 175V as typical L-G/L-N. Guess which one has the higher joule rating? Right - the 175V. But the selection of the 175V MCOV means that the suppression of the SPD does not start until the surge goes above 175V, resulting in a higher LTV (this we do not want). Joule ratings of SPDs are misleading, and this is especially true on the three-phase panel type SPDs. The best residential practice for complete surge protection would be the cascaded or multilayer SPD application. In this case, the SPD is connected at the load center (incoming panel) of the home. A good SPD will have between 40 kA and 80 kA of lifetime rating and should have an LTV of 400V or less. Then apply a good surge strip throughout the home at point-of-use electronics locations. This practice will reduce the surge at two locations and is the best practice to provide effective surge protection. I'm not sure why the Belkin unit has an intermittent ground light, but I would call the manufacturer and inquire about this. It could be a defective unit. Things to remember: Response No. 34: If you are protecting a computer, all devices connected to the computer must plug into the single surge protector. You lose benefit if you plug the printer into another outlet even if it has its own surge protection. VERY IMPORTANT - All forms of communication must also go through that surge protector. In this case, for the computer, the phone line goes from the wall to the surge protector and then to the modem. For a TV - the same idea. The TV, VCR, stereo (if connected to TV), all plug into the surge protector, and cable (and phone if you have pay TV) plugs into surge protector before going to the TV. Buy surge protectors that are "UL
1449 Listed" to be sure they provide minimum protection. It must say listed, not
just "meets or exceeds" or other phrases. It is much better if you also make
sure all utilities (electric, phone, and cable) enter the house at the same location,
and are bonded to a common ground. Even better is to do all of this and install a Class
"B" UL 1449 surge protector on the main panel. Note, this does not replace the
units at each computer and television; it supplements them.
If the member reads the GR1089, he can
get a better understanding of the mechanism. The specs for the products sound to be overwhelmingly
high! But then, how much protection it provides depends on how much inductance there is
between the plane where lightning surge is expected to arrive & the transient protection
devices & their switching speed. This gets us into the inside of the box. Just for
curiosity, I might check out what this box has!
1. Have the ground tested and ensure that the single point method is employed, 2. Install surge protection at the closest point of entry of each utility, and then 3. I would use a point-of-use device
such as the Belkin.
The most critical element of electrical safety, power quality, and surge protection is grounding. If this home's electrical systems' ground does not meet the intent (25 ohms or less), it should be improved to the point where it meets the intent. If your reader is implying that his girlfriend's home does not have a properly grounded outlet, that would be the first thing she should have addressed by a licensed electrical contracting firm with knowledge of grounding and ground testing. Once the grounding at the service entrance and the branch circuits is proper, then surge protection should be installed. The connection of the FCC required lightning arresters on the phone line and connection to the service-entrance ground should be verified. The cable TV and or satellite system must also be grounded properly as well. Miss these steps and all the 2655 joule surge protectors in the world will not save the equipment. To give them a background for a decision as to what AC surge protection will provide and what not to expect: Most down line or connected equipment
warranties are very difficult at best to collect on. Ask your insurance agent if he would
insure anything for a one-time premium that was equal to the cost of most surge protectors.
The warranties are most often full of requirements that are not completed by the purchaser.
Never buy a surge-protection device on the strength of the connected equipment warranty
alone. Most homeowner's and renter policies have a deductible on payment of claims, and
(if you read the fine print) very often that is all you can collect. How hard are you
going to fight for that amount? 1. Is the Product UL 1449 "Revision 2 Listed"? It should state so on the package. 2. What is the UL 1449 testing clamping voltage? Is it 330 volts? (If higher, keep looking) Underwriters Laboratories testing is NOT performance testing, but is about all the testing the average SPD will ever undergo. 3. Is the product well constructed and will the merchant stand behind the product? 4. Is the company that makes the SPDs known for these products or is this just a sideline product they sell? 5. If a phone line protection product, it should be listed to UL 497. There are additional tests that can be performed by manufacturers but most don't bother with performance testing. Still in doubt, contact a company that specialized in such products for their input. There are products not available in retail stores that are higher performance. Question #2 Question #3 Part #2 - Surge protection should be a "layered" or "system" approach. Service-entrance surge-protection devices are highly recommended. Then any sensitive devices should have a second layer of surge protection. This is true of the power, phone and coax lines. The best place to deal with a majority of the energy in an induced surge is at the service entrance. For the most part, SPDs divert the energy of the surge to neutral and ground (in the case of AC power) and ground in the case of phone and coax. The service entrance is the lowest resistance and impedance point of any system wiring to the service-entrance ground. For the layman, the closest place to the surge sewer pipes, ground and neutral. The next step is to provide individual
SPDs in addition to layers of protections. How much is too much surge protection? What
is your exposure? That is measured in where you live (how many days of thunderstorms),
how much you have to lose (money and time), and the big question - how much are you willing
to spend on surge protection to minimize any potential damage. Remember, no one can stop
lightning. If you doubt that statement then watch the sky the next time lightning is in
the area. Lightning travels many thousands of feet, sometimes miles. A good rule of thumb
is 10,000V to the inch. Now, in all honesty, what do you have that can stop that amount
of energy? Response No. 38:
I live in Central Texas, and we are very vulnerable to "thunderstorms" because they are frequent here in the spring and the fall. I have seen the damage that is done to electrical systems due to direct strikes from lightning, and in the majority of time there was a nonexistent, or a very poor grounding system on the electrical service. There has been much research in our National Electrical Code concerning this, and much has been accomplished in the design of proper grounding. My company follows the Code of grounding, and it is important to note the mistakes we have seen in this respect as follows: 1. Improperly installed ground rods, either "cut off" or not as many installed for proper grounding. 2. Improper installation of the grounding conductor. It is important to note, if metallic conduit is used, the proper fittings should be used to connect the ground rod to the conduit. We have found that it is good to be redundant at this connection, by using a conduit to ground rod fitting, and then an acorn-style fitting to bond the grounding conductor to the ground rod. A thermal weld is, of course, a great option there. 3. A lighting strike is like a bear doing what it wills in the woods. If it gets inside, I have seen failures of the best-acclaimed brand of surge protectors. The synopsis is, if you want to properly protect equipment from surges, a properly installed, and well-maintained grounding system is your best bet. It has kept us out of trouble so far in this business, but be aware that a direct hit is impossible to defend against. P.S.: It is curious to me that the manufacturer
of the surge protectors would warranty a "grounded" system, instead of a "grounding
system." Very subtle wording for a very large difference.
The best protection is a layered system
because each product has different voltage clamping levels no matter what the joule capacity
is of the surge device. The first place is at the main electrical service-entrance panel.
Then, secondary protection is recommended at any distribution panels feeding PLC motor
controls or computers. Finally, the point-of-use plug-in devices at the equipment. Be
sure not to forget the telephone, cable, and any other data lines coming into the building
that can carry a damaging surge to the equipment. In your application, both the service-entrance
grounding and the supply-circuit grounding need to be tested and fixed. Without a proper
ground, a surge-protection device will not operate properly.
1. Lightning will do what it wants to regardless of your suppression system. Most of the lower end consumer devices still can be "jumped" by a jolt that wants to get around it. We put too much faith in these units and they don't always do the job correctly. Lightning is very unpredictable (make data backups, make data backups, make data backups)! 2. The best thing this person can do is to have a well-grounded circuit to supply the computer. (NOTE - other pieces of electronic equipment do not always have grounded plugs and therefore do not utilize the surge devices' capabilities, or grounding bus on the panel). One of my recommendations to my customers is to invest in a better quality isolation EMI filtration unit, a surge device, and a power interrupter device (this will stop power from going off and then cycling right back on until electrical conditions stabilize, not to mention most power is so "dirty" that over time it can have an effect on memory, drives, etc.). Look at the sine wave of 120V AC on an oscilloscope sometime and see the "dirt spikes." This person's receptacle and/or circuit may not be grounded properly at all (hence the light flickering). 3. Get a good insurance policy. The claims listed by the manufacturers are very difficult to ever get paid for. Most times a lightning strike will do you a favor and allow you to upgrade to a newer system of device, simply because the technology changes so rapidly. (NOTE AGAIN HERE TOO!) Always keep your data backed up current! I have seen so much time spent with customers rebuilding lost data due to power issues. Yes, whole house surge suppression is
possible. It can be costly, but it's not going to do any good on those units with two-prong
power supplies, etc.
2. The grounding conductor must accompany the circuit from the main to the outlet(s) being used for sensitive electronics. 3. The surge protector being used is probably okay; however, the fact the light flashes and/or goes out indicates a problem with the circuit, or the protector may be defective. 4. All power, telephone, cable and/or other data cables must be protected at the point of entry to the electronic device. 5. A whole house surge protector will protect against a severe lightning surge at the home service point; however, it will not protect other cables entering the home. This is a pretty generic answer to the
question and I see many wiring errors, which do not allow a surge protector to work properly.
1. The joule rating on the surge suppressor describes how much energy the unit can handle during a surge of voltage - the higher the joules, the more rugged the unit. Lightning can emit up to 25,000A and 30 million volts. At this point, it is not likely that any surge suppression device could withstand this kind of surge. 2. The device that is built into the unit can provide a less expensive route for detecting if a ground is connected. There are more expensive ways of testing for grounding but for a computer and answering machine, I would not worry about other testing methods if the unit reads that the ground is present all of the time. 3. It is indeed possible to run surge protection to the whole house. RO Associates recommends that for "proper" surge suppression, there should be multiple units in "layers." That is to say, a suppressor on the main feed, then at each circuit another device, and finally a device 10 ft from the unit(s) to be protected (i.e., computers). The reason for layering is that no surge suppression device can stop all of the transients or spikes. The layers filter out the highest voltages, reducing them until the final filter, which could handle the reduced spike. Finally, RO Associates suggests a surge protection device that can respond in less than one nanosecond (1*10^-9 s) for full surge protection. I saw a similar surge protector (as
the SurgeMaster) get hit by a lightning surge. The components plugged into it were protected
and the manufacturer replaced the surge-protection unit.
1. NOTHING can protect from a direct lightning strike. 2. NOTHING can protect from a direct lightning strike. 3. The surge probably came into the lady's house through either the phone/data (communication) line and/or the power line. The surge-protection device she bought will protect ONLY the devices plugged directly into the protector, and ONLY if they are NOT served by unprotected wires/equipment, like a computer that is plugged into the surge protection but served by a copper line of high-speed communication/data that does not have surge protection. The surge will ride in on whatever line is not protected. 4. "Yes," you can buy surge protection for the entire house that installs at the service entrance. Sorry, but I have to say this: "NOTHING can protect from a direct lightning strike." 5. The solution in #4 is expensive, and should be designed by a registered electrical engineer who has YEARS of SUCCESSFUL design of such systems. 6. The surge protection should be installed by a registered and HIGHLY QUALIFIED electrician, who has YEARS of SUCCESSFUL installation of surge protection. The higher the level of knowledge of both the electrical engineer and the electrician the better; "higher level" meaning people who have designed and installed (several/many?) SUCCESSFUL surge protections in high-end residential, commercial or industrial situations. Grounding and bonding is a somewhat esoteric subject. When you start talking about lightning/surge protection, it becomes downright ethereal. A lot of people will try to sell their stuff, too. And… the KEY to the whole thing is a solidly grounded and bonded electrical system in the house. If it is not, you need someone to advise her on her specific situation and ways to "fix" it. Hope this helps, and, remember: "NOTHING
can protect from a direct lightning strike." If you have questions, please don't
hesitate to contact me.
UL 1499 Second Edition has leveled the
playing field by developing the Suppressed Voltage Rating (SVR) for SPDs. It is a test
method used to assign a SVR value by the UL to a SPD to indicate its protective characteristics.
Each mode of the SPD is subjected to three impulses of 1.2/50us, 6 kV voltage waveform,
and 8/20us 500A waveform. The resultant "measured limiting voltage" is measured
at the ends of 6 in. leads extending from the terminals of an integrated product, or 6
in. extending from the enclosure of a wall-mounted unit. The average of these three measurements
is then compared to a chart. Look for a SVR of 400V or less. The next issue is what kind of device to use - MOV, SAD, or both. The answer is simple - use a hybrid that uses both, SAD as primary and MOV as brute force secondary. SADs are extremely fast and precise devices. SADs can be produced to clamp at very precise voltages and operate in less than five nanoseconds. But SADs cannot handle currents larger than 10 to 20 kA per mode. That is where MOVs come into play. MOVs can handle large amounts of current, but are not as fast as SADs. MOVs operate in the one microsecond range. MOVs tend to degrade after accumulative operation. So, the best devices use SADs for primary and MOVs as brute force secondary. Look for test data that states something like "TVSS is capable of surviving 3500 or more ANSI/IEEE C62.41, category C3 (10 kA) impulses at one-minute intervals" for a Class "C" device. This will guarantee a long-life device. The next problem is installation. Most units are after-thoughts. This leaves you with the choice of using an add-on wall-mounted unit in parallel. This involves wiring to the main or secondary panels, which means lead length comes into play. Lead length exceeding 6 in. practically makes the SPD useless from parasitic inductance of lead lengths. The best method is to use an SPD built into the panels using a "Kelvin Clamp" method of attachment, or a series unit installed ahead of the service disconnect device. The higher-end units also include series filters to further enhance the performance. Now to answer the members questions:
Now onto surge suppression products. A plug-in product is really intended to protect equipment that is plugged into it, not other devices in and around the premises. I'd suggest reading the manufacturer's warranty very carefully because I doubt that they assume liability for direct lightning strikes, unless they have taken a calculated risk insurance-wise. Critical to the effectiveness of a plug-in surge suppressor is the grounding path back to the service panel and premise grounding system. The diagnostics on most plug-in style surge suppressors are only checking for the integrity of the grounding path back to the main panel, and an indication of a problem would suggest an open ground path for example. More critical to the effectiveness, but rarely checked, is the integrity of the premise grounding system - the connections to a ground rod and/or water pipe for example. While a higher joule rating may suggest a more robust design, keep in mind that surges come in all sizes and one could experience many little ones or one really big one before the ultimate end of life of the protective device. The best approach is the use of two-stage protection - a whole house device either installed at the revenue meter or main service panel, and then plug-in devices downstream at electronic equipment that you desire to protect. Generally, the whole house or main panel protection is designed to only protect your hard-wired home equipment and "white goods" - your sensitive electronics equipment still needs the plug-in devices. But when using the two-stage approach, the whole house or main panel device suppresses a large part of a surge incoming on the power line, allowing part of the surge to pass through and be further suppressed by the plug-in protector. The life of the plug-in protector is thus extended by virtue of its not having to suppress much larger surges. And finally, lightning induced surges
can arise on other ports, such as telephone and CATV. Thus, those ports need to be properly
protected with a surge-protection device that has that capability. I hope that this information
is helpful.
No matter what type of surge-protection devices you utilize in your home, nothing will protect your equipment from a direct strike of lightning. With that said, I always recommend to my customers to purchase the devices with the most energy dissipation capacity that you can find (that makes economical sense). I typically recommend trying to find a device for inside the home that has a rating of 1500 to 1800 joules minimum. 2. Would this "SurgeMaster" device provide a reliable means to test grounding, and if it is reading correctly, does that mean the outlet is not grounded? I would not recommend that the surge suppressor be the final means of assuring that you have a valid ground installed. The LEDs in these devices are indicators only, not testing devices. There are several variables, which may cause them to give an erroneous reading. Proper testing of the receptacle where the device is to be used is critical to proper operation and future insurance claims. 3. Finally, if someone does have to come out and run ground for the outlet, isn't it possible to install surge protection at the service to protect the electrical equipment? Surge protection installed at the meter
or main panel typically should be of the Category "A" type. This means that
it is rated to filter out the "bulk" (or large) surges, but will still pass
through a voltage level that could be harmful to electronic equipment. A second stage
of protection (Category "C") is recommended to filter this remaining voltage
to a level safe for electronics. However, the Category "C" devices cannot handle
the large amount of energy associated with a large voltage level, so I always recommend
and install two levels of protection.
Another critical part of the protection scheme is the speed of the protection device. Most lightning surges have a very sharp wave front and so the voltage goes really high, really fast, usually modeled in the 50 nanosecond range, so the protection that is at the computer needs to have very fast response time (less than one nanosecond). Service-entrance protections are usually designed for absorbing lots of energy but have a slower response time. 1. I recommend both service-entrance protection and protection at the critical devices. 2. I am not in a position to judge the ground testing capability of the "SurgeMaster", but I would wager that if it says you have a bad ground, you probably have a bad ground. If it says you have a good ground, then I would question what that means. 3. Answered already. An additional opinion - Make sure the
phone line and cable vision line are grounded solidly to the service-entrance ground.
Failure to do so invites trouble. I personally unplug the telephone from my computer every
time a thunderstorm rolls through (daily in NC).
If you decide to hire an electrician you would just need to compare prices. With the service-entrance protection, you would be protecting your entire house. With the Belkin device, you would only be protecting whatever is plugged into the outlet. Remember, if your house takes a direct
lightning strike it is doubtful that any device would protect your equipment.
SPDs that are identified as Secondary Surge Arresters (SSAs) are tested per ANSI Standards and are not subjected to the extensive testing as SPDs desiring a UL 1449 listing. There is no "safe amount of protection" for your home appliances. However, "adequate" or "reliable" surge protection for one's home appliances is very possible provided that it is installed by a professional. In addition, all of electrical appliances, or any products in the home having any type of electrical or electronic input, must be "effective bonded to earth via a low impedance path." More clearly put, all electrical appliances, equipment, and components MUST be bonded to the SAME ground plane. Your report of "lightning frying her phone, answering machine, and affecting her computer" are indicative of the telephone service, AC service, and cable service entering the home at different sides of the house, and being grounded differently or not adequately grounded at all. Unless there is obvious structure damage to your girlfriend's house, it's highly improbable that lightning struck the house. A more likely scenario is that lightning current passes under the house and a difference of potential developed between the ac power supplies in the electronic equipment, the cable modem, and the phone line. A significant difference of potential was most likely caused because your electronic equipment had different inputs that were grounded at different locations and were not effectively bonded together. If other electrical appliances in the house, such as refrigerators, washing machines, dryers, toasters, microwave ovens, sewing machine (that have only one electrical input) were not damaged, then this is further evidence that the consumer products with two or more electrical inputs were not effectively bonded to a common ground plane via a low-impedance path. The BELKIN "SurgeMaster" is like most other similar products in the residential surge protection market. Most of these types of products contain very small and very inexpensive "nonlinear components" internally connected between the "line" or "hot" lead and the "neutral" lead. The greatest value of such devices that have a multiple ac receptacles, "in" and "out" telephone jacks, as well as an "in" and "out" cable port, is that they provide a common grounding connection that is intended to limit potential voltage rises. The packaging surrounding many such SPDs sold in the consumer market is often more expensive for the manufacturer to produce than the actual internal surge-protective components. Such manufacturers spend significantly more in marketing than manufacturing. 2. No SPD can provide a reliable means to test the grounding system of a home. Grounding test and ground mat testing must be performed pursuant to IEEE Standard 81 by training and qualified professional. However, some SPDs do incorporate a high-impedance illumination circuit that will provide for a light-emitting diode (LED) to illuminate if the resistance to ground is not above a specific value. Be advised that because a green or red LED is illuminated through the cover of a SPD, do not incorrectly assume that the SPD is properly or adequately grounded. 3. Installing a SPD in your service-entrance panel (AC Load Center) or on the electric meter base of the house is highly recommended. However, do not assume that such a device alone will provide adequate surge protection. If your girlfriend wants very reliable surge protection, then the following is highly recommended: (a) Commission a qualified and professional electrical contractor to install at least two new 8 in. x ½ in. copper-clad steel ground rods at different opposite sides of the house. The top of each rod should be a minimum 12 in. below the surface of the ground. (b) Have the electrician bury a single conductor of bare #6 copper wire surrounding the house at a depth of 12 to 18 in. Instruct the electrician to exothermically bond the bare #6 copper-grounding conductor to each ground rod. (c) Instruct the electrician to bond the water pipe, gas line, all telephone services, neutral bus in the surface panel, and cable services to the bare #6 copper-grounding conductor. (d) Arrange for a qualified professional to specify SPDs that are applicable to the geographical region, ampacity and voltage of the power system in your home, and types of electronic equipment in the house. (e) Arrange for a specified SPD containing multiple and heavy-duty nonlinear components to be installed parallel to your electric meter or service panel. Such SPDs are based installed external to your house, if possible. Any such installation should only be performed by licensed and qualified professionals. (f) Arrange for other specified SPDs to be employed within the home. (g) The above will provide the home
with a very good grounding system and sufficient "cascade coordination" of surge
protection to limit the possibility of future equipment damage from local lightning strikes.
1. According to real surge-protection engineers, "joules" is an incorrect way of rating protection because "strikes" are measured in volt/amps, and most surge strips are rated too low to give good protection anyway. 2. The volts in lightning are between 30 million and one billion, with amps between 10K to 200K*(10,000 to 200,000?) with temperatures reaching 50,000 degrees (five times hotter than the sun)! 3. Proper protection should begin at the main service, where the most surges enter. Let's not forget to mention that: (a) Many homeowner policies don't cover lightning strikes. (b) Many insurance companies give discounts for homes with protection. (c) The average home receives over 20 spikes a day (mostly from the utility companies). (d) You can get up to 30 percent more life out of your appliances and equipment using surge protection. (e) Strikes one-mile away can do damage to sensitive equipment. 4. Surge arresters rely on proper grounding for warranty coverage. 5. Panel arresters usually only cover (nonelectronic) major appliances. A/C, washer/dryers, stove, heaters, refrigerators, etc. Proper protection can be purchased in "whole house" kits that come with a panel arrester, (which grounds surges at 150V phase-to-neutral, or 300V phase-to-phase), and wall-type plug-in units that are much more sensitive (130V phase-to-neutral). In the whole house scenario, everything in the house will be covered in the policy. Call: Sycom Surge Protection, Inc.,
Clearwater, FL at 1-800-622-9904. These kits are rated for 150,000A, with a $25,000 repair
or replace policy. |
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