Original Article Date: Jan 20, 2004
Joe Smetona, a Technical Support Analyst with Bentley, contributed this article that provides suggestions for protecting and maintaining computer hardware in the home and workplace.
This article provides suggestions for protecting and maintaining computer hardware in the home and workplace. Many different areas can be addressed to help provide an increased level of protection from voltage spikes, power anomalies, lightning damage, atmospheric contaminants and static electricity.
Maintenance suggestions can help prolong the life of equipment already in service and also may help prevent future downtime. Scheduling periodic maintenance on equipment can significantly decrease downtime due to failures caused by dust buildup, contact oxidation and normal wear of components.
It is important to note that a computer workstation is only a small part of a home or office electrical system. Improving the quality of power to the computer by overall corrections to this electrical system usually will also provide far reaching improvements to other appliances and components within the home or office, many of which also rely on computer control. Lower energy costs may be realized also.
Note: Some suggestions given in this article involve work on 120 or 220 volt live circuits. All work involving household or office wiring should be done by a qualified, licensed electrician.
Factors Affecting Power Quality and the Blackout of 2003:
Electrical Power in the United States is transmitted at very high voltages over long distances. This power can then become part of a larger “Grid”. Substations reduce this voltage to levels which can be used by commercial and residential customers. Further reduction of the voltage is done locally through various types of transformers. Connections are made to individual businesses and homes at these lower voltages.
Typically, a turbine generator set in a power plant will produce 22,000 volts. This will be increased to 765,000 volts and transmitted to other areas of the state or country using the large towers often seen in rural areas. The smaller wires at the top of the tower are called static lines and provide lightning protection. This continuous “cone of protection” helps prevent the high voltage lines below from a lightning strike. Lightning will strike the static lines first (at a higher ground potential), which will protect the wires below. These “static lines” can sometimes be seen across the top of utility poles in your neighborhood. They can help prevent lightning from striking the power lines and tracking into your home or office.
Accidental interruptions or short circuits of the high voltage lines described above will cause large areas of power outages. Protective devices will attempt to isolate a fault and prevent interruption of other areas of the grid. However, there can be a domino effect if the logic of this protection is not correct for the incident at hand. This is extremely rare, but can cause conditions similar to the blackout experienced last year.
This type of failure along with various electrical equipment failures from the substation level to pole mounted transformer level are beyond our control. Their effect on our home or office electrical power is impossible to predict. One outcome of this failure could be the generation of a high voltage spike or surge. If not suppressed, the high voltage spike can destroy sensitive components within computers. Generally, hazardous voltages are most prevalent when the power is disconnected or re-connected. Removing equipment from service by unplugging is the best protection since computers may turn on automatically when the power is restored and be subject to undesired transients.
The best protection available from voltage spikes produced from the above is in the form of a surge suppressor. Normally, a commercially available surge suppressor will also provide a number of protected outlets. It contains a small device varying in size from a dime to a quarter, called a MOV (Metal Oxide Varistor). This device forms the heart of the surge suppressor and will shunt or short voltages above a specified level. This shunting action will prevent the high voltage spike from reaching the sensitive electronics of your computer or appliance. MOV’s may be connected in a number of ways within the surge suppressor and may also be present within the power supply of your computer or other equipment already.
It is important to make sure all of your hardware (using your surge protector) is connected to a properly grounded outlet. Protection from the MOV may be severely compromised if the outlet is not grounded.
A commercial plug-in outlet tester (using three lights) is available for less than ten dollars from major home centers. This will provide indication of how the outlet is wired. It will indicate if a ground connection is present, if the “hot” and “neutral” wires are reversed, if the outlet is inoperative and if the ground terminal on the outlet is wired to the “hot” connection.
If the last condition (ground wired to the “hot” connection) is ever encountered, an electrician should be called immediately and the power should be disconnected from the outlet until repairs can be made. This situation is extremely dangerous and requires immediate attention. Also, the entire electrical service to the home or office should be examined by a qualified, licensed electrician to insure the wiring is safe.
The MOV’s used in surge suppressors also have a definite life cycle. They can only take a finite number of surges and will then fail. They can either fail “open” or “closed”. If the MOV fails open, no protection will be provided to the equipment connected to the surge protector. If it fails closed, the MOV will violently explode, also leaving the equipment at risk. This is why the MOV should always be enclosed in a protective case or housing. It is not possible to predict when an MOV will fail and if it fails open, there is no way to determine if it is protecting the equipment.
At the time of this article, a new MOV is available which will visually indicate that it has failed. As this “Indicating Thermal Protected Metal Oxide Varistor” becomes available in commercial surge protectors, protection of equipment can be reliably monitored. Otherwise, the surge suppressor unit should be periodically replaced, perhaps every 18 months or so to guarantee continued protection. The old surge protector can still be used as a convenience outlet strip for other appliances that are not sensitive to voltage spikes or surges.
Suggestions for Home and Office Protection and Maintenance:
The following suggestions can provide significant improvements in the quality of power delivered to your computer and electrical appliances.
Some areas covered in this article involve adjustments to live 220 volt circuits that cannot be turned off.
Refer items involving live electrical circuits to a qualified, licensed electrician.
Service Capacity - For homes, the circuit breaker panel will have a main circuit breaker controlling all of the circuits wired to the panel. This main breaker is usually larger and has a number engraved on the end of the switch. This number will indicate the overall capacity of your electrical service in amperes. The number is usually 50, 75, 100, 150, 200 or higher. If circuit breakers in your home are constantly tripping, you may need to increase the total capacity of your service. This upgrade would usually necessitate a new circuit breaker panel and could also involve your utility company. They may need to run new, heavier wires to your home from the utility pole or from an underground source. Generally, older homes have lower amperage services and may also use fuses for circuit protection. The article will address circuit breakers only because they are prevalent in most areas. An electrician can assist in determining if your present service requires upgrading based on your electrical power usage.
Also, if the main circuit breaker trips, it usually indicates a very serious condition or the need to upgrade your service. An electrician should be immediately contacted to determine what is causing the main breaker to trip. Loose connections to high current devices such as central air conditioners can cause this to happen and may damage the breakers causing hazardous conditions.
Wiring Integrity – The following suggestions can be addressed assuming that the house or office is correctly wired by using the three light outlet tester mention above.
Outlets, Switches and Power Cords - Replace old, worn or damaged outlets, switches and cords. This is very important since loose connections can damage sensitive electronic equipment. Power cords should be held securely by the outlet, making positive contact. Replace outlets when cracked or cords need to be constantly adjusted to make contact or fall out of the outlet easily. Loose connections anywhere in you home or office electrical system can severely damage or destroy your equipment. Electrical cords may easy become damaged through handling. Periodic inspection of cords will usually reveal areas where the insulation is damaged. Also a cord or plug which is hot to the touch indicates a loose connection where the wires are crimped to the prongs or socket contacts within the molded ends. This is a potentially dangerous condition and the cord should be replaced immediately. This is especially prevalent in high current devices such as toaster ovens, room air conditioners, refrigerators, freezers, etc.
Fires can easily be started from loose connections.
House or Office wiring - KEEP ALL CONNECTIONS TIGHT. This can be done in the following ways:
Contact your utility and investigate if a representative can come to your home and office and tighten the connections in the Meter enclosure. This would involve removing the security seal, removing the meter and tightening the terminals for wires coming from the power source and going to your main circuit breaker panel. These large cables are most likely aluminum and periodically require tightening. All connections most likely will be found to readily accept a significant amount tightening. An anti-oxidation compound is also applied to retard the oxidation of the aluminum conductors. (Ideal NOALOX® Anti-Oxidant Compound). The security seal would then be re-installed by the utility after the above work is performed. Generally, there should be no cost for tightening the meter connections. An electrician can also provide this service for a fee if required. Removing the meter will totally disconnect power from the structure. Fire departments will remove the meter in an emergency situation to disconnect the power.
Similar to the above, the main circuit breaker panel connections can be tightened periodically. (by a qualified, licensed electrician). The screws connecting (black) wires to the main and individual circuit breakers should be tightened along with the screws used to connect the (white) and (ground) wires. All connections most likely will be found to readily accept a significant amount of tightening.
The common method to connect or splice wires in the home or office is the “wire nut”, a plastic cap with an internal conical spring to secure the wires. Unfortunately, in almost all cases, the wires being connected are pushed straight into the wire nut and the wire nut is turned to secure the wires. This provides a marginal connection and is prone to failure due to loosening of the wires over time due to thermal changes. The proper method of connecting wires is to place them together and twist the wires using linesman’s pliers so they are completely secure before the wire nut is screwed on. Electrical tape is then applied to the nut and wires to prevent loosening. This provides an excellent electrical connection independent of the action of the wire nut. It is not practical to re-do your present house wiring connections in this manner, but if you are involved with new construction or remodeling, it is by far the preferred way to increase the integrity of your wiring.
Lightning Protection - Proper grounding throughout your electrical system can significantly enhance lightning protection. It is important to insure all appliances have the same ground potential. If lightning were to strike your home or office, it will seek the highest ground potential it can find, possibly traveling from appliance to appliance as it seeks higher levels of grounding. Again, tight, reliable connections are the key to preventing damage or injury from lightning. Grounding from your circuit breaker panel to the water main (just as it enters the house or office) is the most common method for grounding the system. This is usually done by a bare aluminum grounding wire connecting the circuit breaker panel and water main. A lightning arrestor is normally used for telephone and cable (either cable TV or Internet) protection. These lightning arrestors should always have a connection to the main structure ground described above.
General Maintenance Guidelines - Computers, along with other peripheral equipment can benefit from increased life by scheduled maintenance and cleaning.
Refer to the following link for the Household Products Database listing various cleaning products, full hazard information and their recommended uses. (Courtesy of National Institutes of Health, National Library of Medicine, Specialized Information Services).
One contact cleaner that is safe on most plastics is the CRC QD™ Electronic Cleaner (Quick Drying, No. 05101).
Refer to http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=3003012&query=Electronics&searchas=type for detailed information.
This spray can be used to remove contaminants on the connectors found at the rear of the computer and also sprayed into cable connectors. This spray is flammable and should always be used outdoors with adequate ventilation as outlined on the product label. Electrical equipment should always be completely de-energized and removed from service before using any product of this nature. Follow all label directions and warnings regarding its use and storage.
Invisible oxides and coatings form on electrical contacts rendering them inoperative. This contamination can be attributed to proximity to cooking oils, cigarette smoke, contaminants in the atmosphere and using the equipment in an industrial environment. This coating will build up over time and should be periodically removed from electrical contacts and connectors using the cleaner listed above or an equivalent product safe for use with plastics.
Dust buildup can cause failure of almost all electronic equipment. Generally, removing the equipment from service and vacuuming to remove the dust buildup is best. Accumulation of dust within equipment may cause heat build up. The higher temperature generated from the insulating properties of the dust may change component tolerances causing erratic operation. It may also cause a component to fail from overheating.
High Voltage is present in many electronic devices even after the power is disconnected. Items such as computer power supplies, printers, monitors and other devices should be referred to qualified personnel if opening of the enclosure for cleaning is required.
There is a also significant risk of damaging computers or other electronic equipment (especially memory modules) from static electricity. Static sensitive devices require special handling to avoid damaging the delicate semiconductor junctions present in almost all components in use today.
Never work on a carpeted floor or in any area where excessive dryness is causing static electricity.
The following components can be assembled to create a static controlled working area for any work involving computers or sensitive electronic components.
An aluminum sheet metal plate (approximately 24” X 36”) can be placed on a convenient work surface and connected to a suitable ground (metal cold water pipe, water main entering house, or aluminum wire connecting the circuit breaker panel to the water main pipe) with an 18 gauge wire.
A static control wrist strap can be purchased for under $15.00. The wrist strap wire can then be connected to the plate.
Another wire can be connected to the plate having an alligator clip at the other end. This can be used to connect to the computer case chassis (placed on the aluminum plate) when working on the computer.
Separate sensitive components can be handled as follows:
Place the unopened static safe bag or container on grounded aluminum plate.
While wearing the wrist strap, remove the item from the bag or container and place it on the grounded aluminum plate. Remember to keep all static sensitive items on the aluminum plate. Make sure the wrist strap is worn and connected to the plate before touching any items.
Hopefully suggestions in this article can benefit commercial and residential computer users. It is not practical to determine the cause of computer or component failures without microscopic analysis and an oscilloscope. Many times the defective item is just replaced. Power anomalies causing such damage are virtually invisible and addressing the root causes of the failure most certainly will contribute to longer life cycles and less down time for the equipment.
This article is broad in nature due to the fact that overall improvements needed for the computer and peripherals also involve the entire wiring system of the home or office. Improvements made will benefit all electrical appliances and provide increased economy of operation and safety.
AskInga Article #176