A LAYMAN'S GUIDE TO SURGE "PROTECTORS" by Todd Preston Ooooh I hate that "P" word. The use of the word PROTECTORS is silly, as is the word ARRESTOR. They imply that you can PROTECT your electronics by ARRESTING the lightning. (Fat chance static breath). We should use the word divert...read on to see what I mean. I have seen thousands of dollars spent on sophisticated electronics diversion devices, only to have massive damage occur to the supposedly protected equipment. Why?...because the installers (or salespeople) lacked a fundamental technical grasp of what they were trying to accomplish. You cannot stop a lightning strike. Your job is to divert the energy safely away from your computer equipment. The purpose of this document is to give you the knowledge required to do so. Maybe we can take some mysteries out of the topic, and debunk some myths as we go. Reinforcing your computer and its associated hardware against damaging impulses is an effort well worth undertaking. While equipment replacement is inconvenient and costs dollars, lost data is lost data. The damaging impulses can come from many places, but will enter your computer system by one of two ways. 1. The electrical wall outlet. 2. The telephone modular jack. Protect your computer from impulses coming in on the power and phone lines, and you have effectively built a sandbag dike around your computer system. There is no way to reinforce the roof over your system (diverting a direct lightning strike. Don't bother trying. If lightning blows a hole in your roof, I doubt if you're going to be too concerned about your computer. Damaging impulses can be broken down into two categories: Spikes Spikes are short lived, high level "blips" that ride into your computer on top of the 117 volt level of the power line, or on top of the signal level on the telephone line connected to your modem. If they are large enough, they will usually blow out some components. Spikes have rise times in the nanosecond range, and pulse lengths up to 100 microseconds. They are hard to remove, because they happen so fast. Spikes are usually attributed to lightning strikes, whether local or distant. Their amplitude ranges from hundreds to thousands of volts. Spikes can cause unexplained computer rebooting, system lockup, corrupted data, equipment failure, etc. Surges Surges are longer lived, lower level "waves" that ride atop the 110 volt level of the power line. They have rise times in the microsecond range, and pulse lengths of up to a second. Surges are easy to "catch" because they are slower, but are hard to remove. (Since they last longer, they contain much more power than spikes). Surges are usually attributed to motors: such as air conditioning and refrigeration compressors, drill presses, air compressors, pool pumps, etc. Normally these types of motors pose few transient problems to computers. But when they come on line in a locked rotor state (unable to start to move), or when they blow up, they draw huge amounts of current. This lowers the line voltage. When the fault goes away the line voltage surges big time. During an electrical storm, entire city blocks of "motors" surge after a temporary blackout. With todays electronic switching type of power supply, electronic equipment is less susceptible to surge damage than equipment was say 10 years ago. That's all fine and dandy for manufacturers literature, but I don't want my electronics stuff seeing 375 volts for 250 milliseconds! The answer is the spike/surge diverter, which clamps the high-voltage pulse at tolerable levels. So let's talk about how we can keep those killer pulses out of your electronics. There are products on the market that are sucker buys, and many products that are not. You can pay 40$ for a line cord, outlet, and a 25 cent MOV. You think you're protected, but woe unto you. Diverters come in four generic types. Each type has its strengths and its weaknesses, which are outlined below. A. The special silicon avalanche diode (Transorb) offers:--- + 1. Ideally fast response time. (in picoseconds) + 2. Low level voltage threshold available. + 3 Moderate cost. ( $1.40 ea. @ 100+ quantity) - 1. Catastrophic failure at high current loads (above 500 amps) B. The Metal Oxide Varistor (MOV) offers:------------------- + 1. Very high load current capability. (up to about 5000 amps) + 2. Dirt cheap - 1. Markedly slower reaction speeds. (in nanoseconds) - 2. Effectiveness decays to nearly zero after heavy repetitive activity. C. The lone gas discharge tube offers:--------------------- + 1. Extremely high load current capability. (10,000+ amps) - 1. Even slower response time. (in microseconds) - 2. Crowbar action blows circuit breaker. - 3. High cost. D. The hybrid designs offer:-------------------------- + 1. The best of two or three products, by complementing characteristics. - 1. Highest cost. I use all three components in my hybrid designs. Here's why: The Transorb is the first to react, clamping the spike at the peak voltage level. Before the Transorb blows up from passing to much current, the MOV "kicks in" and relieves the Transorb. If there's enough sustained power in the spike to fire the gas tube (crowbar) then the MOV gets cut some slack. The majority of the manufacturers have gone away from using the gas tube hybrids, and use hybrids that contain Transorbs and MOV's. Some have internal auto reset circuit breakers, RF chokes (10 turns of # 14AWG enameled wire), and other features included in them. Cheaper diverters may offer only one MOV, protecting only one of the three possible power line entry points for a voltage spike ("one-way diversion"). These cheap diverters are out there in mass. Buyer beware. Read the packaging! If you buy in an over-the-counter store, ask the salesperson about the device (if you really are interested in a laugh). As usual, the people at Radio Shack are quite helpful, and frequently quite knowledgeable; so they prove the exception to the rule. The 'Shack offers quality products but does not currently offer anything other than good quality 3-way MOV based diverters. They do offer an excellent line of UPS oriented equipment. It is a tragedy to pay 20$ and up for something that comes in decorator colors and contains a single high voltage value MOV. These "gimmick" products are normally sold in "department/hardware/lumber" type stores. Once again, beware! Non-crowbar diverters are rated according to: response time: time it takes to suppress the spike in nanoseconds clamping level: (the peak voltage ((at a specified amperage)) remaining after the device has sustained a 6000-volt spike) power rating: (the maximum transient energy which can repeatedly be absorbed without failure, measured in joules). Since there are three power "legs" to protect in any circuit, true diversion boils down to meaning a three-way line network. Line (hot)-to-neutral -- (called differential or normal mode) Ground-to-line --------- (called common mode) Ground-to-neutral ------ (also called common mode) Most manufacturers describe this as: Line to Line -- (differential mode) Line to ground -- (common modes) HOT NEUTRAL LINE 1 LINE 2 GROUND ³ ³ GROUND ³ ³ ³ ³ ³ ÉÍÍÍÏÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÏÍÍÍ» ³ ÃÄÄÄÄÄÄÄÄÄÄĶ GAS TUBE ÇÄÄÄÄÄÄÄÄÄÄÄÄ´ ³ ÈÍÍÍÑÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÑÍÍͼ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÉÍÍÍÍÍÍ» ³ ÉÍÍÍÍÍÍ» ³ ÉÍÍÍÍÍÍ» ³ ÃÄÄĶ VR 1 ÇÄÄÄÄÅÄÄÄÄÄĶ VR 2 ÇÄÄÄÄÅÄÄÄÄĶ VR 3 ÇÄÄÄ´ ³ ÈÍÍÍÍÍͼ ³ ÈÍÍÍÍÍͼ ³ ÈÍÍÍÍÍͼ ³ ³ ³ ³ ³ ³ ÉÍÍÍÍÍÍ» ³ ÉÍÍÍÍÍÍ» ³ ÉÍÍÍÍÍÍ» ³ ÃÄÄĶ MOV 1ÇÄÄÄÄÅÄÄÄÄÄĶ MOV 2ÇÄÄÄÄÅÄÄÄÄĶ MOV 3ÇÄÄÄ´ ³ ÈÍÍÍÍÍͼ ³ ÈÍÍÍÍÍͼ ³ ÈÍÍÍÍÍͼ ³ ³ ³ ³ ³ ³ ÉÍÏÍ» ÉÍÏÍ» ³ º L º º L º º 1 º º 2 º ÈÍÍͼ ÈÍÍͼ For ease of illustration, two grounds are shown. VR1-VR3 are transorbs. (avalanche diodes) L1-L2 are home-made chokes made of 10 turns of #12AWG insulated wire This is the type of device that you would install as your #2 defense. (At the output of the sub-panel 117v breaker that feeds your computer) SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS WARNING WARNING WARNING WARNING WARNING ALL OF THE TECHNIQUES, PROCEDURES, AND IDEAS CONTAINED HERE- IN DEAL WITH DANGEROUS 117/240 VOLT AC CURRENT. DO NOT ATTEMPT ANY INSTALLATION OR MODIFICATION YOURSELF. CONTACT A QUALIFIED ELECTRICIAN FOR ASSISTANCE. ALL THE FOLLOWING STATEMENTS APPLY TO STANDARD 117/240 VOLT SERVICE ONLY. FOR ANY 3 PHASE OR 440 VOLT PLUS CIRCUITS, YOU'RE STUPID IF YOU DO NOT CONTACT A LICENSED ELECTRICIAN FOR ASSISTANCE WARNING WARNING WARNING WARNING WARNING SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS Somebody smack me If I digress a few hundred more times...but here's an important clarification of terms, their use, and the criticalness of you understanding them. We are bridging two totally different technical fields here, one being Electricity and the other being Electronics. Terminology between the two is just close enough to be dangerous. MAIN DISTRIBUTION PANEL: There is a "Main Main" circuit breaker that is after the meter, which feeds all the breakers in the Main Distribution Panel. This Main Breaker will feed such circuit breakers as: House Main, Outbuilding Main, Garage Main, Air Conditioner, Pool Pump, Arc Welder, Outdoor Lites, etc. You can think of this Main Breaker as your property's Main Disconnect. If you kill this breaker your shop loses power, along with your toaster, your sprinklers, and your porch light. REMEMBER, THE HOT SIDE OF A BREAKER IS HOT, WHETHER THE BREAKER IS ON OR OFF!!!!!!!!...When you trip your "Main Main", the PANEL IS STILL HOT AND CAN KILL! SUB PANEL: Your Property may have several sub panels. Each sub panel may or may not have its own "Sub Main" breaker. You would have a sub panel in your house, in your garage, etc. (Every place you have that is a "separate entity") The typical sub panel would normally have its own sub main breaker, feeding multiple different breakers. Rephrased, Each meter on your property should feed only one Main Distribution Panel, which should feed one or more independent Sub Panels. A pictorial............... ÉÍÍÍÍÍÍÍË ÉÍÍÍÍÍÍÍ» ÉÍÍÍÍÍÍÍ» ÉÍÍÍÍÍÍÍÍÍÍÍÍÍ» ÉÍÍÍÍÍÍÍÍÍÍÍ» º º º º º º º º º JONES º º HIGH º º º º JONES º º JONES º º º ºVOLTAGEº º º º º º º ºSUBPANEL"A"º º º º TRANS º º º º MAIN º º º º POWER ÇĶ FORMERÇÄÂĶ METER ÇĶ DISTRIBUTIONÇÄÂĶ INSIDE º º LINE º º º ³ º º º PANEL º ³ º THE º º º º º ³ º º º º ³ º HOUSE º ÈÍÍÍÍÍÍͼ ÈÍÍÍÍÍÍͼ ³ ÈÍÍÍÍÍÍͼ ÈÍÑÍÍÍÍÍÍÍÍÑÍͼ ³ ÈÍÍÍÍÍÍÍÍÍÍͼ ³ ³ ³ ³ ÉÍÍÍÍÍÍÍÍÍÍÍ» ³ ³ ³ ³ º JONES º ³ ÉÍÍÏÍÍ» ÉÍÍÍÏÍÍ» ³ º º ³ ºJONESº ºJONES º ³ º º ³ ºPOOL º ºSTREETº ÀĶSUBPANEL"B"º ³ ºPUMP º ºLIGHT º º º ³ ÈÍÍÍÍͼ ÈÍÍÍÍÍͼ º INSIDE º ³ º THE º ³ º GARAGE º ³ ÈÍÍÍÍÍÍÍÍÍÍͼ ³ ³ ÉÍÍÍÍÍÍÍ» ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» ÉÍÍÍÍÍÍÍÍÍÍÍ» ³ º º º º º º ³ º SMITHSº º SMITHS º º SMITHS º ³ º º º º º º ÀĶ ÇĶ MAIN ÇÄĶSUBPANEL"A"º º º º DISTRIBUTION º º º º METER º º º º IN THE º º º º PANEL º º HOUSE º º º º º º º ÈÍÍÍÍÍÍͼ ÈÍÍÍÍÍÍÍÍÍÍÍÍÍͼ ÈÍÍÍÍÍÍÍÍÍÍͼ The wire going to the screw of the circuit breaker is the hot line FOR THE DEVICES FED BY THAT BREAKER. NOT THE HOT INPUT TO THE BREAKER. If your panel is wired properly, this breaker output wire (device input) will be a black (hot) wire for 117v breakers, and a black (hot) & a red (hot) OR a black (hot) & a white (hot) for the ganged or two pole 240v breakers. (( The coloration here depends on your local code, the age of the installation, and whodunit)) There will be two buss strips located on the side of the panel. One will be the connect point for a bunch of white (neutral) wires, and the other will be the connect point for a bunch of green or bare copper (ground) wires. Depending on the physical characteristics of the gas tubes and hybrid diverters, and whether the main distribution and subpanel are surface or flush mounted, you may end up having the electrician install them 3-4 feet from the panels. They will have to be connected using code approved methods. Two lengths of 1/2" Sealtite and four Sealtite connectors will usually be acceptable, but you must check your local code to be sure. First, let me describe an ideal diversion system for those of us on a budget. You can easily spend 10,000 dollars or more on grounding grids, Ufer grounds, dissipative arrays, etc. Lets save those for the rich. We'll do almost as good a job, at low cost. Keep in mind that lightning diversion is system oriented. That is, one facet of the system can be the best possible, and if any other portion of the system is deficient or ailing, then the whole system isn't work a hill of beans. Even though some of the diversion components are electrically installed in parallel with the line, the diversion route is one simple series circuit. From cloud to a good earth ground. The old loggers had the "a chain is only as strong as its weakest link" adage. I guess that's why all those sayings were developed. (because they're true) Anyway, here we go. 1. A gas tube device at the building main distribution panel, installed after (on the cold sides of) the main circuit breaker that feeds the house subpanel. (NOT THE MAIN THAT FEEDS THE MAIN PANEL). You want your gas tube on the cold side of the House Main. See prior clarification. I'm assuming your computer is in your house. If you're working in your garage, change the words that read "...feeds the house", to read "...feeds the garage." APARTMENT DWELLERS: This can nearly be an impossibility for those of you that live in an apartment. However, I have had good success with going to the Maintenance Supervisor of the property, and explaining to him what I wanted to do. Ask him to show you the meter room, this is where you will do most of your dirty work. There are separate meters for each apartment, and these separate meters feed a small main distribution panel for your specific apartment. This panel will have an apartment main breaker, along with possibly another for an air conditioning condensing unit. You'll add your gas tube device here, after the apartment main. It must be installed on the cold side of the apartment main breaker. (the side feeding your apartment, not the side coming from the meter). Worst case, the utility company can be contacted to rotate (disconnect) your meter while the electrician installs your device. HOMEOWNERS: At least you can do what you wish on your own property. (sort of). You still have to follow all the electrical codes for your State, County, and Municipality. These codes are there for your protection, so don't snoot at them. Locate your meter, and your main distribution panel should be right underneath. Hopefully it is surface mounted, and not flush mounted. Surface mounts are so much easier to work with, because you don't have to rip the wall apart to wire in the gas tube device. The gas tube is installed on the cold side of the Breaker that feeds the HOUSE SUBPANEL. See prior clarification. 2. A hybrid at the house subpanel, placed on the cold side of the circuit breaker controlling the wall outlet you will be using. I'm assuming your computer is located in your house. If you're working in your garage, then change the words ..."house subpanel" to ..."garage subpanel". (If your breakers aren't labeled, here's the opportune time to do so.) Plug a portable radio into the desired outlet and turn it up. Trip a breaker off (wait 2 seconds) and back on, one by one, till the sound goes away. You'll be dealing with a breaker that has only one "leg". That is a single 120 Volt breaker. Any that are ganged together (trip one, another trips) or take up two slots in the panel, are 240 Volt breakers. These would feed (supply power to) items such as: water heaters, stoves, dryers... They better not be feeding your outlets! 3. An off the shelf 3-way MOV spike diverter screwed captive into the DEDICATED duplex receptacle that will be serving your computer equipment. Screwed captive means that the MOV diverter is provided with a screw that holds the device to the duplex receptacle. Most require removing the outlet cover first. This last line defense is the package that contains two RJ-11 modular phone jacks that will be labeled in/out, from phoneline/to modem, or something like that. Spike diverters using MOV's should have a colored MOV status lamp which goes out if the MOV fails. In this failed condition, the spike diverter will still usually pass electrical current through to the equipment, but the current will no longer be spike diverted. After you have had the electrician install whatever diversion devices you elect to use, you may think that you are all set. NOT! You have diverted the damaging spikes and surges, but to where? The lightning was looking for a way to get to a good earth ground, that's why it hit in the first place. You have to give the spikes and surges a real easy path to divert to or they will "laugh" at your attempts. The most expensive diversion devices are useless unless there is an easy path for the diverted spikes and surges to dissipate into the earth. I can tell you right now, that the schmutzy ground rod that the power company drove into the dirt 5 years ago near the base of the meter is not a satisfactory earth ground. So here's what to do to make the whole project gel. Don't get disheartened, it's kinda fun. What you are going to do, is drive some ground rods in your lawn with a sledgehammer, and then connect them all together with bare copper wire. Spend an hour or two figuring your materials list using the included worksheet and flowchart. Don't hesitate to barter for some of the items, tools, or labor. If you know your materials supplier, try trading them a ground network installation at their home for your materials and tools. Substitutions are fine on some items, and are noted where applicable. If your residence has any utilities that enter your home via underground cables; (phone, cable TV, electric, etc.); you must locate those cables before you do any digging. As a point of reference, the utility companies are responsible for maintenance on the cables up to and including the demarcation device. 1. Call the appropriate utility company and tell them that you are going to be digging in your yard, and you'd like them to come out and mark (locate) their lines so you won't damage them. Most utility providers are ecstatic when people ask before they dig. When you call, ask them their name first and write it down. If you get a negative response from the 1st contact person, go up one supervisory level and try again. (get the name before you ask). (If still negative, advise them you will hold them personally liable if you are injured or damage anything.) Ask for a date that the locator will arrive, and if possible, meet them. 2. Watch them operate the detector, and don't hesitate to ask questions. They may locate your water input, if it's not PVC pipe. Leave their flags intact while you do your rooting around. I've known the locators to blow it big time, and have seen a 2 foot diameter hole augered right through a 50 pair phone cable. The digging contractor was not liable in any way, because the utility company had "located" (albeit incorrectly) the lines. On a sheet of paper, sketch the top view of your house, electric meter, and telephone demarc. Include major trees, hedges, swimming pools, driveways, etc. (as if you were in a hot air balloon looking down) You are going to be doing this to scale, so let 1" equal 2' or whatever. -------------------------------------- End of Lightnin Divert P1 9/9 I am debugging the flowchart required for the next steps. They should be ready in a week (HA). There will be a parts listing, sources, and maybe a glossary as well as digging and driving instructions. [Lightnin Divert P2 X/Y] ... Coming soon at your local theater. My Thanx to John Mudge for assisting in the proofreading, and suggestion offering department. Todd