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  • Grounding

    Grounding System (part 1 of several parts)

    Few topics can elicit as much controversy as grounding. Poor grounding practices can cause continual equipment problems in a facility, whereas proper grounding practices can ensure reliable and productive facility operation. Specialized grounding techniques have evolved to meet the perceived grounding requirements of electronic equipment performance but sometimes also violate the NEC®. Terms such as single point grounding, multiple point grounding, isolated grounding and equipotential reference grounding have special meaning and illustrate different approaches to grounding.

    What must be understood:

    •The difference between floated and grounded electrical systems.
    •The adverse effects of voodoo grounding schemes.
    •Why isolated ground receptacles work in some cases and not in others.
    •How ground plane technology prevents skin effect from defeating equipment grounding.
    •Why and how telecommunications and cable TV systems must be grounded.
    •The disadntagesofFaradaycageconstructiontocontroleffec tsofradiatedinterference.
    •How to preserve NEC® (life safety) grounding compliance and still achieve effective grounding without sacrificing equipment performance.
    •Recognizing grounding as a simple scientific practice rather than as magic, myth or folklore. (Source: letter, Tom Shaughnessy, PowerCET, August 5, 1992, to William J. Warnock, President, Warnock Security Solutions, Inc.)

    Poor grounding can cause difficulty with sensitive equipment. The Computer and Business Equipment Manufacturers Association® (CBEMA®) recently stated that 75% of all power-quality problems are related to poor grounding. An extensive grounding system that keeps potential differences throughout the facility grounding system to a minimum is essential. (Source: “©Handling Nonlinear Loads,” by T. L. Barber, Consulting-Specifying Engineer® May 1996).

    “Multi point Grounding System Keeps Airliners Flying High.” Because a power outage at the Hampton, Ga., Federal Aviation Administration (FAA) center could have a major impact on air travel in the Southeast United States, a Multi point grounding system, with a signal reference grid, is helping ensure added protection and error-free operation at the facility. The new system is part of a nationwide effort by the FAA to improve reliability of air-traffic control operations.
    Because today’s high-speed digital equipment is subject to high-frequency electrical noise and transients that can disrupt data processing, the standard “green-wire” ground used in many situations was by itself, determined insufficient for FAA retrofits. For some computer circuits, a transient of only one-volt is enough to cause unpredictable and intermittent data loss or even equipment failure. Yet, power-line transients of hundreds or thousands of volts are not rare.
    Consequently, consulting engineers from Ralph M. Parsons Co. And members of a FAA power committee decided FAA control centers would be better served by a system that provides Multi point bonding between interconnected equipment, with many parallel paths to ground. This arrangement prevents any voltage difference between pieces of equipment.
    The system specified incorporates a prefabricated signal reference grid made of flat copper strips welded together into series of two-foot squares. The grid is laid on bare concrete under the computer-room raised floor, and everything in the room — including computer equipment, conduits, water piping, ducts and steel building columns — is bonded to the grid using exothermically welded connections and braided copper straps. After laying out the grid, which is supplied in 12-foot-wide sections, rolled up like carpeting, the raised floor is placed on top.
    The grid itself is connected by No.4 AWG cable to a main grounding plate in a central power building next to the control room. The main grounding is then routed outside to a 500-thousand-circular-mil (mcm) counterpoise around the building exterior. (Source: Consulting Specifying Engineer®, December 1996 issue, page 18, “©Technology In Action.”)

    An electrolytic grounding system, such as the Lyncole XIT™ should be considered as an excellent alternative to driven rods. Personal Communication System (PCS) equipment operation is extremely sensitive to ground resistance variations causing effectiveness of earth ground to be vitally important. (Source: Power Quality Assurance®, January/February 1997 issue, page 69, “©Electrolytic Earth Grounding for Communication Equipment Protection,” by Elizabeth Robertson, Lyncole XIT Grounding)

    (1) Has the building grounding system been divided into at least 4 subsystems?

    (a) Earth electrode?

    1 Determine how the building is grounded. Is it bond-grounded through structural steel?

    2 Are there separate grounding electrode systems in different parts of the building? Look at the power entrance(s), the telecommunications entrance, and any computer-communications-electronics areas. Are there any elements that aren’t grounded together? If no grounding systems are found, or if isolated systems are found that need to be bonded together, recommend the services of an experienced and knowledgeable electrical contractor.

    3 Inspect as many of the connections as possible. Look for signs of corrosion, loose, or missing connections. Recommend repairs if necessary.

    4 Suggest and arrange for a grounding electrode system resistance check, see number (9) below. Check it at different times of the year especially in cold and dry weather. If the resistance is not less than 10 ohms (), consider recommending upgrading the grounding electrode system. This may be done by installing a grounding electrode ring or electrodes buried in concrete.

    5 If a satisfactory grounding electrode system is in place, determine how to connect the entire security system to it, to include all peripherals. Some examples of this might be bonding the security system to the structural steel, if it is the grounding electrode system, or grounding bars connected to the grounding electrode system.

  • #2
    (Part 2)
    (b) Lightning protection?

    According to writer and humorist Dave Barry: “The Encyclopedia Britannica tells us that lightning is ‘giant pieces of electricity that live inside clouds and periodically attack golfers.’ The best way to avoid being struck is to stay away from areas where golfers might be present, such as sand traps, bars, recreation rooms, your office and outdoors.” Humor keeps us sane, but there is a deadly serious side to lightning.

    *Lightning is a force of nature that fascinates us, as much as makes us fear it. Once considered an uncommon occurrence, lightning actually hits the earth about 100 times per second. That makes about eight million strikes per day! The United States alone experiences over 20 million strikes per year. Scientists have estimated that at any given moment there are nearly two thousand thunderstorms occurring over the earth’s surface. That means about one hundred thousand thunderstorms annually for the US.

    Cloud to ground lightning occurs when negative charges at a cloud’s base are attracted to positive ones on the earth. A surge is created which carries current to the ground. This bolt typically contains about one billion volts and between 10 and 50 thousand amperes of current. What happens next is called a “return stroke,” which is revealed as the bright flash.

    The average lightning stroke is about six miles long, however; strokes up to 100 miles long have been documented. The flash, up to an inch wide, appears wider than it actually is due to the glowing air surrounding it. Lightning’s return stroke can reach 50,000 degrees Fahrenheit. To put this blast in perspective, the surface of the sun is only about 11,000 degrees. Therefore, lightning is about five times hotter than the sun’s surface. A single bolt can yield enough power (20,000 megawatts) to satisfy a day’s electrical needs for the entire state of Arizona.

    Lightning may occur even with a clear sky overhead. A thunderstorm need only be within 10 miles for cloud to ground lightning to originate from high altitude anvil clouds. The thunder that follows the lightning bolt can be heard up to 10 miles away. The relative likelihood of a particular structure being struck by lightning varies with the keraunic level, i.e., thunderstorm activity in the locality, the effective height of the structure, and its attractive area. The average thunderstorm activity is plotted on an isokeraunic map that is available from the National Weather Service. Normally thunderstorm activity is from March through October, peaking in June, July, and August. Strong lightning is expected to accompany any thunderstorm especially in the peak months.

    Thunder is essentially the air around the lightning exploding due to high temperature. Lightning “cooks” the surrounding air to between 15,000 and 50,000 degrees Fahrenheit. The sound is relative. If the strike is close by, the louder the thunder’s “bang.” Rumbling thunder is the “clap” arriving at a different time due to distance and the length of the lightning.

    When attempting to protect sensitive electronic equipment, the observance of “The 30-30 Rule” may not be of much help for the many reasons listed previously. The rule’s observance is one of personal safety from the effects of lightning. It is well established that as little as 17 milliamperes (mA) of electrical current can stop the heart beating. As an aside, consider that it takes 50 mA to trip a 20-ampere circuit breaker. The rule employs the “flash-to-bang” theory, the time lags between a lightning flash and the sound of thunder, wherein one counts 10 seconds from the flash to the bang; the lightning is about two miles away. That means taking shelter immediately if the flash-to-bang interval is less than 30 seconds, indicating the lightning is within six miles. And it means waiting 30 minutes after the last thunderclap or flash before resuming outdoor activity. It need not be raining for lightning to strike. So-called “heat lightning,” a flash without thunder, is not harmless. It is simply too far away for its thunder to be heard — yet! As indicated above, many storms 10 miles wide or wider, and the phrase “bolt from the blue” is not merely a figure of speech.

    Nearly 100 Americans are killed by lightning each year. Nearly 300 are struck and survive. Annual property loss in the United States due to lightning has been estimated into the hundreds of millions of dollars. Much of this damage is to sensitive electronics that suffered surge damage as the result of a nearby lightning strike. (*Source: compiled with information from The Weather Channel, Automated Weather Service, Inc., NOAA, and Global Atmospherics, Inc.) The reader’s attention in invited to the book, “©All About Lightning,” written by Doctor Martin Uman, Professor of Electrical Engineering at the University of Florida at Gainesville, and http://www.ligntningsafety.noaa.gov/outdoors.htm

    1 Is the Risk Assessment Guide of NFPA® 780, Installation of Lightning Protection Systems, followed in all cases for all structures? As every building varies in design and construction, a tailored system must be created for each structure.

    2 If a system is in place, were it and the installation contractor certified by the Lightning Protection Institute (LPI) as specified in Standard of Practice, LPI-175? Lightning protection technology is a specialty discipline and the expertise required for system design and installation is not available through many general practice-engineering firms. Certification assures national codes NFPA® 780 and UL® 96A are met.

    3 Air Terminals — also referred to as lightning rods; these copper or aluminum rods are vertically mounted on a structure’s roof or top at various high points. Positioned to protect above the roofline, the rods are designed to intercept lightning strikes.

    4 Main Conductors — made of copper or aluminum; these cables connect air terminals to grounds. Conductors are coursed inside the framing spaces during construction of the building, hidden from view and protected from corrosion. On existing buildings conductors may be coursed behind down spouts or other parts of the building.

    5 Grounds — main conductors are attached to metal ground rods that are set at least 10 feet deep in the earth. Special grounding requirements are sometimes necessary in sandy or rocky soil.

    6 Bonds — the bonding connects grounded metal objects to the main conductor cable and prevents side flashes (lightning jumping between two objects). (*Source: “©A Bit About Bolts,” by Marian Perkowski, Lightning Protection Institute®, September, 1997 issue, Security Dealer Magazine®.)

    (c) Fault protection?

    1 Check the service entry switchgear and all transformers. Are the neutrals bonded to the grounds at these power sources? Are the transformers bonded to the building grounding electrode system, and not just to a locally driven rod?

    2 Measure the current on the grounding electrode conductors (connections between the transformers and the grounding rods). There should not be any. If significant currents, more than five amperes are encountered, encourage and arrange for a complete power survey.

    3 Look inside power panels to verify that the neutrals are isolated from the grounds. Also, measure the current on the A, B, and C phases. They should be balanced. If there is more than a 10% unbalance, this can cause undesirable currents on the security system. Measure the current on the neutral wire. There should not be any, although high neutral currents are now a significant problem with solid-state devices. Avoid if all possible connecting access control, fire, and security systems to these panels.

    (d) Signal reference? See also Articles 645 and 647, NFPA® 70.

    Consider installing a signal reference grid (SRG) in computer-command centers, where high-speed mainframe computers are present. An SRG is not the same as a “grounding” system.

    Options:

    1 Raised-floor system. Description: Steel stringers. Construction: Bolted connections. Relative Cost: Low initially, high maintenance. Effectiveness: Unpredictable.

    2 Field-build wire grid. Description: No. 6 round copper wire: 2 to 4 foot centers. Construction: Bolted or crimped connections. Relative Cost: Medium to high installation, maintenance may be needed. Effectiveness: Low to fair.

    3 Pre-engineered SRG. Description: 2 inch by 26 gauge flat copper strips: 2 to 4 foot centers. Construction: Exothermic welded connections. Relative Cost: Low to medium, no maintenance. Effectiveness: Excellent.

    4 Prefabricated wire mesh. Description: Solid round wire: 6 to 24 inch centers. Construction: Brazed connections. Relative Cost: High, no maintenance. Effectiveness: Excellent.

    NOTES:

    The building’s steel has a higher inductance at frequencies below one megahertz compared to copper’s low inductive value.

    Flat strips with large surfaces are more effective at dispersing unwanted electrical noise because they lower impedance that round cables, even when the cable size is increased. (Source: Power Quality Assurance®, July/August 1996, page 75, “©More Than the Green-Wire Ground,” Al Turner, Project Manager, Cochran, Inc., Seattle, WA).

    Designs must follow Electronic Industries Association-Telephone Industries Association® ©Standard 569, Recommendation for Grounding Bars and Proper Bonding in Telecommunications Rooms.

    Comment


    • #3
      (part 3)
      (2) Are the building’s grounding systems:

      (a) Equipotential?

      (b) Constructed uniformly?

      (c) Distributed throughout the building?

      (d) Accessible?

      (e) Low in resistance?

      (f) Maintained separately by technical and non-technical loads?

      (g) Are interior furniture and finishes static dissipative? (See J.14.aa. below.)

      (3) Is conduit used as a ground or is a grounding conductor used in all instances?

      (4) Is grounding of the neutral done correctly, i.e., at the service entry panel, at all separately derived devices (transformers, generators, and UPS only and nowhere else, i.e., in outlet boxes or in power panels?

      (5) Where is the grounding system located and what gauge wire leaves the service entry panel?

      (6) What is the primary method used? (Connection to a cold water pipe is normally the primary method.)

      (7) What is the secondary method used? Is it buried below the permanent frost line? (Secondary methods normally consist of a counterpoise system, ring around the building, single or multiple grounding rods, or rods forming an equilateral triangle.)

      (8) What is the condition of the electrical grounding system?

      (9) When was the system last tested?

      (a) Make and model of equipment used?

      (b) Which method of testing was used? Fall in Potential Method? Simplified Fall of Potential Method?, Slope Method?, Dead Earth Method?, The 61.8% Rule?, The Intersecting Curves Method?, The Star Delta Method?, Nonlinear Method?, Wenner Method or 62% Method? The Dead Earth, 62% Methods, and the 61.8% Rule are not recommended.

      (c) Was the test conducted within 72 hours of meaningful rainfall?

      (d) Was there an odor of urine or ammonia present when the test was conducted?

      (e) Was there evidence of chemical treatment? If so, what kind(s)? How recent?

      (f) When the topic of power grounds comes up, the focus tends to be on the earth ground system itself, whether a single ground rod, mat, or grid system. While a low effective resistance is very important, the ground conductor and the terminations on that conductor will often be overlooked. A fault current has to pass through every connection on a conductor before it can reach the earth to be safely carried away.

      Testing of the effective resistance of a ground is important, but a good testing program must include the ground conductors and its connections and splices. The electrical ground system ultimately includes the grounded device itself, and the entire pathway back to the earth ground.

      The impedance of the ground conductor can be seen as the pathway that a faulted current will have to take to reach the earth ground system. When insulation fails, a short circuit occurs. Protective devices like fuses or breakers open to stop the fault current, but before these devices can act, the ground conductor must carry the fault current to the ground rod in the earth.

      The effective ground resistance needs to be as low as possible to quickly and safely dissipate the fault current for two reasons: First, the fault current has to quickly exceed the rating of the protective device, or exposed metal will be energized, and potential for catastrophe exists. If the fault current does not exceed the rating of the protective device, the current will continue to leak on the ground continuously, until a complete failure occurs. Second, the fault current and resistance of the ground system can be multiplied together to calculate the effective voltage at the ground. Imagine that a ground system has an effective resistance of 50. A person standing in mud on a job site may have a lower pathway to ground, say 30. If that person is unlucky enough to touch the bare ground conductor when a five amp fault current is present, the 5 amp current at 150 volts may well pass through his body rather than the ground itself, since he has a lower effective resistance than the earth ground. If the effective resistance of the earth ground were at the NEC® recommended 25, virtually all of the fault current would flow through the intended pathway to ground, not through the person’s wet feet. This is a very good reason to treat exposed grounds as if they are always energized. You do not ever want to become a ground conductor.

      A similar condition occurs in a building when splices or bonds on ground conductors are not low resistance, or when the neutral and ground is connected at a sub-panel. A high resistance bond on the ground will produce high impedance to fault current. This naturally causes heat as well as increasing the likelihood that the fault current will find a path to ground other than the ground conductor. Here again, someone unfortunate enough to become a lower pathway to ground could suffer the consequence.

      This high resistance bond can be a source of power quality problems as well. Modern digital electronics work at 5-volt levels or less, switching, communicating and controlling our automated industrial processes. Imagine the problems fault currents cause when they produce voltage on the groundside of solid-state circuits. This common problem can be resolved completely by providing low resistance pathways for fault current to follow to earth ground.

      Another related power quality issue is stray voltage. Very commonly caused by connecting the ground and neutral conductor in a sub-panel, stray voltage can energize all exposed metal and building steel. Stray voltage in dairy farms causes cows to eventually stop giving milk, and in hospitals will cause many problems with high tech diagnostic equipment, and patient connected equipment. In our modern electrical environment, non-linear loads cause high neutral currents.

      The neutral conductor can carry substantial current back to the earth ground system. The ground conductor is not considered an electrical conductor, and is present to provide a low resistance pathway for fault current. The neutral must be carried back to the service entrance, and can only be bonded to the ground conductor at the main neutral buss, where a large copper conductor carries all the return and faulted current back to the earth. Sometimes through error or ignorance, the neutral and ground are connected upstream from the service entrance. This is called a false or bootleg ground. If the neutral and ground are connected anywhere else in the building, all grounded metal becomes part of the neutral conductor, constantly energized and creating various voltage potentials on electronic equipment. This causes many nuisance problems with automated equipment and computers, but can also create a hazardous and expensive electrical environment.

      The solution to these problems is to include complete ground pathway testing as part of the standard procedure in your facility, and to choose test equipment which will help you locate and identify high resistance ground paths, and locate and eliminate bootleg grounds. *(Source: Pathway to ground: Pathway to Improve Safety and Power Quality,” by Brian Blanchette, Ideal Industries, T&M Division, ©Utility Products Showcase Magazine®, August, 2001.

      Comment


      • #4
        (part 4)
        i. In the service entry panel (fuse or breaker), are the breakers cool, warm, hot, or very hot to the touch? Are individual transformers cool, warm, hot or very hot to the touch? If very hot, what is the interior cabinet temperature? Are transformers noisy, slight hum, loud hum, or annoying loud? Have parallel connected panel mount transient voltage surge suppressors (TVSS), metal oxide varistor (MOV) type been installed? If the answer is yes, list names, models, and parameters. Have they been located as close as possible to the panel to be protected? If not, explain why not? What are the conductor sizes and lengths of connecting leads?

        j. Does the electrical system exhibit any of the following symptoms?

        (1) Fuses or circuit breakers blow or trip often? Which circuits are most affected?

        (2) Lights that flicker when equipment is turned on? Which lights are more affected than others? Some lights burn out more frequently than others. Which circuits?

        (3) AC ripple (vibration to the touch) present on equipment chassis? Is AC rippling constant or intermittent? Seasonal? At what times was AC ripple the strongest or most noticeable? Shock or electrocution is possible under the right circumstances.

        (4) Equipment that does not operate at full power? Which equipment is more affected than others?

        (5) *Trouble Signs: You probably know that if a circuit breaks when your turn of an appliance, that’s a sign you’re overloading your work site or your home’s electrical system, or that a problem exists in the wiring or the appliance. But did you know there are other warning signs to watch for? For instance, these are also signs of problems in your electrical system: your lights dim, your toaster doesn’t toast, your iron doesn’t heat up or the picture on your computer or television screen shrinks.

        *On or Off? You may believe that your equipment is turned off by turning it off, it’s not “live.” But in fact it is, if the equipment is plugged into a working outlet, it’s on! That means you could still get a shock if the equipment is faulty or if it comes into contact with water. If you don’t want the equipment “live,” unplug it for safety! (*Source: © Northern Virginia Electric’s ® Cooperative Living ®, February 2006)

        (6) Is there interference to television or computer screen images when a microwave oven is in use? With commercial television, is there interference noted? What channels other than two through four (54 to 72 MHz)? What electrical circuits cause this interference?

        (sub paragraphs k and l not included due to transfer problems and not really necessary)

        m. Is the exact location of each wire run known? Is this borne out by architect or contractor as built drawings? Have modifications to the electrical system been recorded or added to existing drawings? (This will be critically important if an alarm system is to be installed in the building.) (sketch and measure)

        (1) The drawings and the narrative prepared for a project must contain information how much separation that will be maintained between cabling carrying high voltage alternating current (AC), low voltage AC, and low voltage direct current (DC).

        (2) There should be at least 12 inches of horizontal and 6 inches of vertical separation between conduits and/or conductors carrying AC from those carrying DC.

        (3) The primary purpose of both ferrous metal conduit and separation is the attenuation of the magnetic lines of flux (interference).

        n. What are the grade and condition of each electrical switch and receptacle used in the building? (If the switch is turned on and it is moved from side to side, does the light flicker? Are receptacle slots and switch fronts routinely vacuumed of dust or other debris? Is there an established practice of vacuuming each switch and receptacle at a minimum of every six months? Do plugs stay in the receptacle without the prongs being pinched or spread apart? Is the tension good on each receptacle? Does it meet the 10-ounce pull test? Provide name and model of tension tester? Is there any kind of buzzing or hissing coming from any of these devices? Is any device hot to the touch?) See NFPA® 70B, Recommended Practice for Electrical Equipment Maintenance.

        The electrical system plans must require NEMA configured, premium industrial grade, nonlocking 125 VAC number 6598-HGI, 5-15R or number 6898-HGI, 5-20R ground fault circuit interrupter (GFCI) receptacles to be installed in all dwelling unit “bathrooms,” garages, outdoors where there is direct grade level access, crawl spaces, unfinished basements within 6 feet of a wet bar sink or kitchen sinks in new construction or renovation. Further, in other than dwelling units GFCIs will be installed in bathrooms and on rooftops of commercial, industrial and all other nondwelling occupancies will be GFCI. Installation techniques as outlined in paragraph 2, above will be used. The NEC® has required the GFCI since the NFPA® 70-1981 edition. The purpose of the GFCI is to de-energize an electrical circuit when as little as five thousands of an ampere is present as a fault in the electrical appliance or receptacle being used, thus preventing severe shock or electrocution. As little as 17 milliamperes (mA) can stop the heart! Normally 50mA are required to de-energize a 20-ampere circuit breaker. The lack of GFCIs should be viewed as an exploitable security weakness, and as such, the installation of regular duplex receptacles should not be permitted. Article 210-8, NFPA® 70 applies.

        o. How is each electrical switch and receptacle wired? (Is wire attached to binding post screws, quickwire push-in terminals, or rear wiring ports with binding post compression?) (Is correct polarity maintained - black wire on brass colored screw, white wire on chrome colored screw, red wire on brass or chrome colored screw, green or bare copper wire on green colored screw?) (If white wire is a current carrier, is it marked with black paint or tape at every point where the wire can be accessed?) If receptacles and/or switches are to be replaced, it is highly recommended that, as a minimum, these replacements be limited to industrial grade back and side wired Leviton® brand name and number or equal.

        It is further recommended that only the back wiring ports be used to insure 100% skin contact between receptacle and wire. After the bind post (screw) has been compressed, the wire with the correct amount of insulation removed is fully inserted into the port. With the wire firmly held in position, the binding post is then tightened until snug. The post will then be tightened an additional ½ turn or 1.36 Newton meters (N•m) or one pound foot. The process is repeated until all connections are made. The tightening process is the same for the green grounding screw.

        p. Was the electrical system ever tested for the presence of high frequency noise or the quality of electrical service being supplied? What were the make and model of test equipment used? If so what were the results?

        q. How are datamation and other sensitive electronic equipments, to include copy machines, protected from the harmful effects of unreliable electrical power? (See “©The Conspiracy of Electronics And You Pay For It!” John Pecore)

        Comment


        • #5
          It is my hope the foregoing will be of benefit. I had to learn, like many others, the hard way. SecTrainer is quite correct, grounding and bonding problems are the bane of the security industry, and others.
          Enjoy the day,
          Bill

          Comment


          • #6
            Can't thank you enough, Bill. I've printed and will be reading this material for some time.

            This is the real value of the Internet, in my opinion. Through forums like this, as well as mail servers, blogs, and of course email, we now have access to experts like Bill, who might be anywhere in the world, and can learn from them.

            I know we take it for granted, but this is an amazing leap forward in information sharing. Think about it: Today, any ordinary Joe living in Smallville USA is able to count among his friends and acquaintances perhaps several dozen or more of the top experts in his field and many dozens of other colleagues, and he can "sit on a virtual stump" with any of them, sharing ideas and knowledge, solving problems and avoiding mistakes that others have made. I think I have a ground loop problem; I can take it to Bill, whom I would not even have been privileged to know if not for forums like this. We have Curtis, Nate, CameraMan, Mike Silva, Integrator and too many others to mention who bring us the benefit of literally hundreds, if not thousands, of years of experience so that we don't have to reinvent the wheel every single day. This kind of thing has real-world, everyday value as well as personal value that is impossible to measure - and that's not even counting the billions of terabytes of "print" information that can be accessed as well as practical everyday solutions like driving directions, locating products and services, etc.

            Personal story: I had a client system where the BIOS password had been set, employee under investigation, and you can't crack or change BIOS passwords except (in some cases) by flashing the BIOS. Unfortunately, this requires booting from the A: drive, which meant changing the boot order, and the BIOS was blocking access to the setup routine. The motherboard battery was also fixed, not removable. A classic "Catch-22" situation. I raised the question with a forensics colleague who is an expert in password issues and whom I had met on a forum like this one. I was asking whether he had any way to crack this password that I didn't know about, but his solution was much more simple, brilliant, and I would never have thought of it: Disconnect the hard drive data cable from the motherboard connector, and the motherboard would be forced to boot from the A: drive. Ten minutes later, I had flashed the BIOS, reconnected the hard drive and was ready to start imaging the drive.

            I know that a lot of you young whippersnappers don't even know what life was like before this kind of global connectivity was possible, but I do, and it's really a remarkable transformation - one that is much more profound than the Industrial Revolution. When we're tempted to think of the Internet as this dark place where pedophiles, identity thieves, con artists, terrorists and other sociopaths hang out, we should realize that the benefits of the Internet unquestionably outweigh the downside. And, in particular, we should remember that we probably couldn't have the positives without some of the negatives. Just ask people in China.

            Bravo, Bill!
            Last edited by SecTrainer; 01-07-2009, 12:28 AM.
            "Every betrayal begins with trust." - Brian Jacques

            "I can't predict the future, but I know that it'll be very weird." - Anonymous

            "There is nothing new under the sun." - Ecclesiastes 1:9

            "History, with all its volumes vast, hath but one page." - Lord Byron

            Comment


            • #7
              Thank you for those kind words SecTrainer. When you have a major fire in a federal courthouse due to inadequate grounding and a failure to adjust transformer taps to accomodate for an addition or reduction of loading that is a tragedy of the first magnitude.
              For instance, I took this this from January 6, 2009 edition of EC&M's MRO Insider:
              Repair "Electrical Troubleshooting Quiz
              Winter solstice is now behind us, so the days are getting longer again. Yet, your facility seems drearier. Being the sharp electrical troubleshooter that you are, you grab a light meter and take some measurements.
              When you review your findings against the lighting plan, your suspicions are confirmed. Light levels really have dropped. In some places where the plan shows 45 footcandles, you measured only 25. In an inspection area that requires 90 footcandles, you measured 70. How can you figure out what’s going on?

              The answer to this question appears at the end of this newsletter.

              Quiz Answer
              Answer to Electrical Troubleshooting Quiz
              A drop in light output is hard to isolate in time, because it tends to creep up on us. As light output diminishes a little each day, we adjust to the new normal. That makes troubleshooting more difficult, but not impossible.

              Light output diminishes as lamps near end of life (the output curve varies by lamp type). So, maybe it’s just be time for relamping. However, there are probably other factors to correct. Things to check include:

              Dust and grime accumulation. Are the lamps, lenses, and shades clean?
              Overloaded neutrals. A plastics plant in Kentucky solved a dim lighting problem in one building by rewiring the lighting system. Most of the neutral wires had overheated to the point of discoloration. This rewiring more than doubled some footcandle readings.
              Transient protection deficiencies. Is your surge protection (Art. 285) plan tiered so that it protects lighting ballasts from events generated from inside your facility? If not, you probably have damaged ballasts. Replace a few ballasts to see the effect. Correct the protection deficiencies.
              Bonding deficiencies. Walk down your lighting system for violations of Art. 250, Part V. You should not have connections to ground (as defined in Art. 100) anywhere in this system."

              Bonding and grounding again reared its ugly head. Thanks again for your kind words SecTrainer. I have learned from you and many other members of this forum you've mentioned and many others. I no longer have a "Security Checklist." It is now a "Security Checklist Booklet."
              As security professionals, we must constantly pick the minds of other members of the business or corporation concerning what they notice or "feel" and what impact it has on the mission, yes mission, and then do our level best to ferret out the problem and be a part of its solution.
              Leadership must see through our deeds that security is in the ROI business in mission support.

              //////Geoff, I know you review these threads. Is there any possible chance you could "cause to happen," neat term I learned in Air Force NCO Leadership Courses, an article published in Security Technology Executive, dealing with these technical problems that plague all of us? /////

              Enjoy the day,
              Bill

              Comment


              • #8
                Out of all the things I've learned on this forum in the past few days, I believe I will use the term "cause to happen" the most.

                I would also like to thank SecTrainer for including me in such august company.
                The CCTV Blog.

                "Expert" is something like "leader". It's not a title that you can ever claim for yourself no matter what you might know or might have done. It's a title that others bestow on you based on their assessment of what you know and what you have done.

                -SecTrainer

                Comment


                • #9
                  CameraMan humble man that I am feel honored that to have added in some minute way to your vast pool of knowledge.
                  Lord knows I heard that term often enough in my military career and again as a civilian employee within DOD.
                  Enjoy the day,
                  Bill

                  Comment


                  • #10
                    Boys and girls, thank you for the heads-up emails. Yes soil, weather and surrounding environment do affect grounding. With that in mind the following is submitted:

                    2. Soil Characteristics

                    a. What type of soil is between the building and the property boundary? (Sand, loam, clay, rocky, fill-dirt)

                    b. Determine the extent, if any, of sub-surface strata such as peat bog, hardpan or shelf rock to a depth of one meter.

                    c. Determine average and maximum expected frost depth. Determine average length of seasons that soil is frozen.

                    d. What are the average water table, its extremes and its seasonal variations?

                    3. Weather Factors (Obtain local climatological data from the National Oceanic and Atmospheric Administration (NOAA), National Climatic Data Center, Asheville, North Carolina 28801.)

                    a. What is the average monthly rainfall in inches?

                    January
                    February
                    March
                    April
                    May
                    June
                    July
                    August
                    September
                    October
                    November
                    December

                    b. What is the average monthly temperature ranges?

                    January
                    February
                    March
                    April
                    May
                    June
                    July
                    August
                    September
                    October
                    November
                    December

                    c. How often is there fog in the area? (Number of days in a month - morning, night, thick, and patchy which months are the worst?)

                    d. How often does it snow? (Months, inches which months are the worst?

                    e. How long does the snow stay on the ground? (Month to month)

                    f. What are the extreme wind velocities? (Month and average peak velocity and duration)

                    g. How often does the area have ice storms? (Frequently or occasionally)

                    h. How often is there cloud cover? (Percent coverage, day or night which months or seasons are the worst)

                    i. How often does the area have lightning? (Which are the worst months and frequency, based on the isokeraunic maps?)

                    4. Industrial Environment

                    a. Are there any high-tension lines close to or above the property on which the building is located? (Note distance from building and location of pole or stanchion on drawing or sketch)

                    b. Are there electrical transformers near the property line? How many far away and in which direction─ north, east, south, or west? (Note location on drawing or sketch)

                    c. Are there any sewer lifts, pump houses, welding shops, and quarries with excavating machinery, air conditioning equipment, water pumps, and agricultural equipment on or near the building? (Note distance and location)

                    d. Are there any roads close to the building? (Note the distance and location from the perimeter boundary)

                    e. Are there any major roads or interstate highways close to the perimeter boundary? Within 2,000 yards or 1,828.8 meters? What are the peak hours of traffic? (Note distance and location on drawing or sketch)

                    f. Is there any railroad tracks close to the perimeter boundary? Within 2,000 yards or 1,828.8 meters? How often are they used? (Note distance and location on drawing or sketch)

                    g. Is there an airport close to the building? Does the landing/takeoff pattern or flight path go over or come close to the building? What is the minimum altitude? (Note distance and location on drawing or sketch)

                    h. Is there a ground radar site close to the building? (Note distance and location on drawing or sketch)

                    i. Are transmission towers (television, radio, or microwave) close to the building? (Note distance, location and frequencies if possible on drawings)

                    j. Are there maritime installations close to the building? Within 2,000 yards or 1,828.8 meters? What is the activity? (Harbors, canals, or channels?) (Note distance and location on drawing or sketch)

                    k. Are there streams, rivers, or lakes adjacent to the building? Is a complete flooding history available? Are they navigable? Within 2,000 yards or 1,828.8 meters? What is the activity? (Daily, weekly, seasonal or year round?) (Note distance and location on drawing or sketch)

                    SecTrainer you are a true friend.
                    Enjoy the day and thanks again everybody,
                    Bill

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