rc property bul electricalpreventativemain cna

8/22/2019 RC Property BUL Electricalpreventativemain CNA

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Risk Control BulletinElectrical Preventive Maintenance & Inspection

Statistics indicate that more fires start from electrical sys-tem failure than from any other cause. Electrical equip-ment is usually well designed and properly installed. How-ever, the principal reason for electrical system breakdownis the failure to maintain the installation in its designedstate.

As soon as electrical equipment is installed, normal dete-rioration begins. If left unchecked, the deterioration proc-ess can cause malfunction or complete failure. Perform-ance and life expectancy of the equipment are decreased

by factors such as environmental conditions, system over-load or excessive duty cycles on equipment. These fac-tors when combined with neglect can result in prematurebreakdown.

Instituting a preventive maintenance program which con-sists of routine inspections, tests and service of electricalequipment can significantly reduce the potential for break-down. Without an electrical preventive maintenance pro-gram, your facility assumes a risk of serious electrical fail-ure and the heightened potential consequences of fireand/ or production interruption.

Advantages of an Electrical Preventive Maintenance Pro-gram

Effective electrical maintenance program has specific ad-vantages including, but not limited to the following:

Reduces accidents and possibly even saves lives. Provides maximum freedom from breakdown during

normal operation. If breakdown were to occur, down-time would be significantly reduced.

Controls the cost of maintenance repairs and equip-ment replacement. Maintenance costs can be effec-tively budgeted versus large, intermittent expendi-tures.

Maintains equipment at peak operating efficiency.This is often seen in reduced operating costs resultingfrom improved efficiency of electrical consumption.

Improves employee morale since employees will beconscious of management's efforts to promote safetyby reducing the likelihood of electrical equipment ac-cidents which can result in injuries or even fatalities.

While the advantages resulting from improved safety aredifficult to measure directly, the economic statistics can

be tracked by reduced repair costs and equipment down-time. The investment in preventive maintenance is smallcompared to the cost of repairing equipment damage.

Instituting a Preventive Maintenance Program

Starting an electrical preventive maintenance programrequires the support of top management. It is top man-agement who must provide funds to initiate and maintainthe program. It must be a conscious management deci-sion to implement an effective electrical maintenance pro-gram since substantial commitment is necessary.

When considering the start up of an electrical preventivemaintenance program, the basic planning begins withidentifying some important factors - the "what if" ques-tions:

Personnel Safety - Should a failure of the electricalsystem or major electrical apparatus occur, will thesafety of personnel be endangered? Has every pre-caution been taken to protect the worker from electri-cal injury?

Equipment Breakdown - Is the electrical equipmentcomplex and so unique that should a breakdown oc-cur repairs would be expensive?

Production Interruption - Should equipment becomeinoperable, will repair or replacement require exten-sive downtime? Consideration must be given to avail-ability of spare parts (foreign versus domestic equip-ment). What effect would the loss of a vital piece ofequipment have on overall production dollars?

These are key considerations in building an effective elec-trical preventive maintenance program. The degree towhich the program is implemented and the frequency ofmaintenance will be dependent upon the answers to theforegoing questions.

The degree to which an electrical maintenance program is

implemented is influenced by several factors:

Location Size - 2,000 square ft. versus 250,000 sq. ft.

Business Operation - mercantile versus industrial.

Type of Plant Equipment in Use - Lighting fixturesversus large, rotating electrical apparatus.


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Risk Control BulletinCombustion Controls

Consequences of electrical failure - relatively minor incon-venience versus substantial downtime or economicloss.

Based on these factors and the consideration of eco-nomic costs, management will select one of three types ofelectrical maintenance programs.

1. Unscheduled Maintenance - Repairs in response tobreakdown, also known as "breakdown maintenance."

2. Ordinary Maintenance - Repairs, adjustments or re-placement of parts shown to be necessary by visualinspections at irregular intervals.

3. Preventive Maintenance - Regularly scheduled inspec-tions and periodic dismantling of equipment to checkevery detail likely to cause trouble. This is the pre-ferred method.

Obviously, unscheduled maintenance is least preferred,but is most common and widely practiced. It must be un-derstood that implementing an electrical preventive main-tenance program is not an easy task to accomplish. Thereare production scheduling considerations, budget require-ments and the need to have the electrical systems in-spected, tested and maintained by personnel specificallytrained in electrical maintenance.

The lack of maintenance or periodic system inspectionscan increase the potential for unneeded nuisance inter-ruptions or critical breakdowns during peak operationwhich can result in lost production and lost profit. The im-plementation of an effective electrical maintenance pro-gram will satisfy an important part of management's re-

sponsibility; keeping costs down and production up.

Value of an Effective Electrical Maintenance Program

The cost of preventive maintenance is small compared tothe cost of repairing extensive damage. Expensive timeconsuming repairs are often the result when unexpectedtrouble develops in electrical equipment which is impor-tant to business operations and plant production. Majorelectrical changes found necessary by periodic inspec-tions can usually be planned to have the least impact onthe overall operation. Equipment can be shut down whenits effect on output is minimal. Unscheduled maintenance,however, is necessary when an electrical apparatus failsunexpectedly and can seriously affect operations.

A regularly scheduled, effective electrical preventivemaintenance program is the most important factor in cor-recting electrical defects, reducing equipment failure andthe resulting breakdown costs, and protecting personnelagainst injury.

Essential Components of an Electrical Preventive Mainte-nance Program

1. Assign qualified personnel. Where appropriate, pro-vide maintenance personnel with formal training, pref-erably by the equipment manufacturer or authorizedservice provider. For many metal finishers, contractmaintenance makes good economic sense with theprime factors being the lack of competent, qualifiedpersonnel, extent and frequency of maintenance, orthe complexity of the equipment. This is particularlytrue when performing thermal scanning of apparatussince a certain degree of interpretation of the resultsis necessary.

2. Establish the necessary maintenance requirementsand priorities. Equipment should be analyzed to de-termine the extent of the required maintenance and

where the program should begin. As a minimum, allimmersion heaters, rectifiers, motors, transformers,circuit breakers, controllers, and protective devicesshould receive a thorough inspection and evaluation.Upon conclusion, a qualified judgment can be ren-dered as to how, where and when each piece ofequipment can be worked into the program.

3. Initiate routine inspections and tests. Manufacturer'srecommendations should be followed as a minimumwith frequency increased for critical components orsevere service conditions. Some testing may have tobe performed during operational shutdowns. Gener-ally, for continued reliable operation, switchgear com-

ponents should be cleaned, inspected and checkedfor tightness of electrical connections on an annualbasis. Electrical testing of insulation for indications ofdeterioration or faults should also be performed on anannual basis. At the same time, protective relays andcontroller can be tested for proper operation and re-calibrated, if necessary, by a qualified contract ser-vice.

4. Analyze inspection test reports so that proper correc-tive measures can be implemented. Evaluate the datato determine equipment condition which will revealrepair work needed. It will also help determine thefrequency of required inspections and tests as well as

the cost estimates. Whatever frequency of inspectionand maintenance is established, it should be adheredto for several maintenance cycles and modified sub-

ject to experience. Equipment that consistently goesthrough two maintenance cycles without requiringservice may have the interval between inspections


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Risk Control BulletinCombustion Controls

increased by 50%. Equipment subject to frequentbreakdowns between inspections should have theinterval decreased by 50%. As the frequency of in-

spection and maintenance is increased, it is antici-pated that breakdown or unscheduled maintenancewill decrease until an optimal level of preventive main-tenance is reached. At this point, overall costs includ-ing breakdown maintenance and loss of productionwill be at their lowest levels.

5. Perform the required work. Follow through with appro-priate corrective action after the inspections are com-pleted and the test reports analyzed. Performing nec-essary repair work, replacement and adjustment isthe end result of an effective preventive maintenanceprogram. Keep a sufficient supply of replacementparts recommended by the equipment manufacturerto avoid downtime and extended lead time. Remem-

ber, the worst time to perform maintenance is when itis unscheduled. Do not procrastinate.

6. Maintain complete and accurate records. Maintainingrecords is an invaluable tool in planning, budgetingand in evaluating the overall effectiveness of the pro-gram. As a minimum, it is suggested that nameplatedata, purchase information, test and/ or start-up(acceptance) specifications and any applicable infor-mation from the manufacturer be kept for comparisonpurposes. Also, document emergency contacts andphone numbers of repair companies and equipmentsuppliers as well as lead times for replacement parts.Care should be taken to avoid excessive record keep-ing since that may hamper the program.

7. Periodically re-evaluate the preventive maintenanceprogram. Annually review the inspection and test re-ports as well as the replacements and failures to de-termine if the program is meeting its objectives and toverify that all information is current.

Inspection Frequency

Those pieces of equipment identified as critical to busi-ness operations should require the most frequent inspec-tion and testing to assure continued reliability. Otherequipment should be inspected and tested but it can usu-ally be with much lower frequency.

Most electrical equipment manufacturers provide a rec-ommended frequency of inspection within their servicemanuals. The frequency listed is normally based on"standard or common" operating conditions and environ-ments. The manufacturers cannot provide accurate fre-quencies for equipment exposed to unusual combinations

of environment and operating conditions. Those specifica-tions, however, are a good basis from which to begin con-sidering the frequency of inspection and testing.

Frequency, of course, can be varied depending on oper-ating conditions. For example, electrical switchgear lo-cated in a room which is clean and operating at ambientconditions would be tested based on manufacturer's rec-ommendations.

If that same switchgear were exposed to dust or corrosivevapors, the test frequency may be doubled.

Whatever frequency of inspection is established, it shouldbe adhered to for several maintenance cycles unless fail-ures occur. For equipment subjected to failures the inter-val between inspections could be reduced by 50 percent.If equipment consistently goes through two maintenancecycles without requiring service, the period in betweeninspections may be increased up to 50 percent.

As the frequency of inspection and maintenance in-creased, it is anticipated that breakdown or unscheduledmaintenance will decrease until an optimal level of pre-ventive maintenance is reached. When this occurs, over-all costs, including breakdown maintenance and loss ofproduction, will be at their lowest levels.

Fundamentals of Electrical Preventive Maintenance

Most effort has been directed toward initiating an effectiveelectrical preventive maintenance program to reduce thepotential for a serious electrical interruption. The basicrule applying to all electrical apparatus is to keep it clean,

keep it dry, keep it tight, and prevent friction.

Clean Dirt is a common cause of electrical failure. Dirtis the day-to-day accumulation of particulate matterfrom the atmosphere consisting of dust, lint, chemical,metallic particles, oil mists, spray residues, etc. if al-lowed to accumulate, it can contaminate electricalequipment causing overheating and increased electri-cal resistance. In some applications heavy contamina-tion cannot be avoided. This is typical of foundries,mills, quarries, cement plants, grain elevators, etc. inthese applications, special apparatus designs are ap-propriate. Every effort, however, should be made tokeep equipment free to particulate matter. This in-

cludes activities such as weekly cleaning of motor cas-ings and keeping electrical cabinets free of dust byvacuuming. Every maintenance opportunity shouldinclude a thorough cleaning of apparatus.


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Risk Control BulletinCooking

Automatic Extinguishing Systems

DryElectrical equipment operates best in dry and corro-sive-free atmospheres. Humidity accelerates the oxi-dation of metals used in the electrical gear. Oxidebuild-up increases resistance thus reducing effectivecontact and the resulting heat can lead to eventualfailure. High moisture levels can lead to direct shortcircuiting and immediate failure. Humidity should becontrolled if possible and guarded against by usingequipment designed for use in damp or wet conditions.Some typical example of high moisture areas or wherethere is an exposure to moisture or corrosion included:dairies, laundries, canneries, tanneries, meat packingplants, locations near seashores, swimming pools,metal plating, and areas where acids and alkali chemi-

cals are used, handled or stored. Tight

Many electrical components operate with high speedmovement while other electrical equipment may notmove at all. Motion of operating equipment will eventu-ally cause wear and imbalance. Appreciable imbalancetends to create vibrations in equipment and loosen vitalconnecting parts. Routine maintenance is necessary todetect wear and loosening of parts and connections.This should include a check for tightness of accessiblehardware and bolted parts as a simple precautionarymeasure. Tightening a screw or connection takes but amoment. It can prevent hours of searching for intermit-

tent trouble. Friction Free

Electrical equipment that is operating properly hasminimum of friction, however, there is always the po-tential for mechanical breakdown as a result of in-creased friction. Friction can result from numerouscauses. Some of the most common reasons includemisalignment of equipment, excessive wear and thefailure to properly lubricate. Some electrical apparatusdoes not require lubrication nor should it be performedunless specified by the manufacturer. Over-lubricationis a dangerous practice because excessive oil can col-lect dust and abrasive materials and even oxidize into

difficult to remove deposits on the machinery. Lack ofrequired lubrication will significantly add to overheatingof the unit and may eventually lead to failure. Machin-ery must be properly lubricated at recommended fre-quencies. Alignment of machinery components is criti-cal to help reduce friction. Machinery which is squeak-

ing may be the first indication that friction problems aredeveloping. Equipment operators should be instructedto be alert for signs of faulty operation or unusualequipment sounds. The key element is maintenance.

The information, examples and suggestions presented in this material have been developed from sources believed to be reliable, but they should not be construed as legal or other professional advice.CNA accepts no responsibility for the accuracy or completeness of this material and recommends the consultation with competent legal counsel and/or other professional advisors before applying thismaterial in any particular factual situations. This material is for illustrative purposes and is not intended to constitute a contract. Please remember that only the relevant insurance policy can provide theactual terms, coverages, amounts, conditions and exclusions for an insured. All products and services may not be available in all states and may be subject to change without notice. CNA is a registeredtrademark of CNA Financial Corporation. Copyright 2010 CNA. All rights reserved.

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