Maximizing the Return on your Infrared Electrical Inspection Investment
InfraMation 2012 Application Paper Submission
Bob Fink
A1 Infrared Inspections
ABSTRACT
Infrared thermography is proven to be the best way to inspect and maintain electrical systems and can guarantee savings in electrical usage, downtime, and fire and loss prevention. Whether you choose to contract for an infrared professional, or handle the job in-house, you will be investing a sizable amount of money and time. This discussion will present methodology to maximize the efficiency and effectiveness of your infrared electrical inspection. It will include the basic parameters for any electrical inspection in general as well as site-specific recommendations.
BASIC PARAMETERS
Every IR electrical inspection will have three basic components: a) the infrared technician; b) qualified personnel to open and close all equipment to be inspected; and c) individual(s) familiar with the locations of all panels and equipment included in the defined scope of the inspection. Quite often one person will play multiple roles. For safety, the inspection team should always include two or more persons.
The Infrared Technician – This is the person who will be using the IR imager and documenting and interpreting the findings. In some instances, the IR technician will also be qualified to assist in opening panels.
Qualified Personnel – One or more persons properly trained and qualified to open live electrical panels. These persons should be familiar with the mechanics and operation of all equipment being inspected, as well as NEC and OSHA safety regulations. More often than not, one or more of these persons are also the individuals familiar with the facility and the location of all equipment to be inspected.
Inspection Coordinator – Individuals familiar with the facility and the locations of all equipment to be inspected as well as any specific scheduling requirements. These individuals should also be properly trained in safety and emergency procedures. Most often these responsibilities are also fulfilled by the persons acting as Qualified Personnel.
SCHEDULING
The first step of your IR inspection is, of course, scheduling. A little forethought at this stage can greatly improve the overall effectiveness of your inspection.
Scheduling Considerations – General
Peak Loads – Scheduling your inspection during peak load and production times is essential in maximizing its effectiveness. Although this may pose challenges, the benefits almost always outweigh the extra effort. There are several site-specific exceptions that will be discussed later.
Personnel – Make sure the necessary persons are going to be available. Things will go much smoother if the lead electrician is not on vacation.
Site-Specific Scheduling Considerations – These factors will be discussed later in this paper.
PRE-INSPECTION
A little extra planning at this stage can dramatically increase the efficiency of your inspection by helping to avoid delays and save time. Whenever possible, it is best to include individuals who will be performing the inspection in the discussion and planning as well as management.
Define the Inspection Parameters – Make a list of all locations and panels to be inspected. Be sure to include outdoor and rooftop equipment as well as any off-site locations, i.e.; water treatment facilities, well heads, lift stations, etc. This is especially true if you are contracting for your infrared services. As a general rule, the thermographer is not going to be familiar with your facility.
Review Panel Labeling – This is a good time to make sure that all panels being inspected have an in-house label. These labels will help identify panels in which anomalies are found and avoid confusion at the time of repairs.
Review Equipment Details – Check to ensure that all personnel involved in opening panels are familiar with panel locations, mechanics, and opening procedures. Make sure any special wrenches or tools that are needed will be available, as well as any keys required for access. Consider installing viewports in large and high voltage panels for easier, safer access. Determine if any panels can safely be opened prior to the inspection. This is often an easy way to maximize efficiency in your inspection. Some facilities have panels in closets or rooms that can be secured from unauthorized access. These panels can be opened in advance of the inspection to save time.
Coordinate with Utility Providers and On-Site Contractors – If your list of equipment to be scanned includes utility-owned transformers, be sure to call ahead and schedule someone to open their equipment on the day of the inspection. Most providers will be glad to have their equipment inspected as long as you give them advance notice. The same holds true for on-site contractors such as elevator maintenance companies.
Coordinate Internally – Inform all security personnel, department heads, managers, crew leaders, etc. in advance of the inspection. Discuss possible scheduling, production, safety, and personnel conflicts that may arise.
Review Safety Procedures – Review all safety procedures and make sure all personnel involved have the proper Personal Protective Equipment on hand at the time of the inspection. Also review emergency procedures to ensure all personnel involved know what action to take in the case of an accident.
Consult Your Thermographer – Should questions arise during your planning, do not hesitate to contact your thermographer. It is what you are paying him for.
DETERMINING THE INSPECTION AGENDA
The order in which you conduct your electrical system inspection can maximize both its effectiveness and efficiency. Some factors that affect nearly every commercial and industrial electrical inspection agenda include:
Weather – When the forecast calls for clear skies, bright sun, and high ambient temperatures, outdoor equipment with exposed elements (substations, transmission lines, pole-mounted transformers, arresters, insulators, fuses, etc.) are best inspected before dawn or after sunset to minimize the effect of solar loading. Although an experienced thermographer with proper equipment can find problems despite solar loading, the more the effect is minimized, the quicker and more accurate the diagnosis will be. Check the daily forecast for rain and schedule accordingly. Most IR cameras can handle light rain (a plastic grocery bag makes a handy impromptu lens protector); however, removing panel fronts or opening cabinets in the rain is never a good idea and should be avoided.
Production Schedules – Attention should be paid to all production schedules in your facility. For example, in some food, dairy, and snack production as well as some manufacturing facilities, the departments at the beginning of the production line (unloading, mixing, etc.) are done for the day andcleaning up long before departments at the back end of the production line (packaging and shipping). There are some other site-specific considerations that we shall discuss in a few moments.
Load Distribution – Consideration of your facilities daily load distribution will also help maximize your infrared investment. For example; in residential applications and hotels, panels feeding individual units or guest rooms have the largest loads in the evening hours when they are occupied, so a second shift inspection of these panels may be in order. Large HVAC systems (chillers, cooling towers, and associated pumps) are best inspected in late afternoon in warm weather when they are working the hardest.
Panel Location/Facility Layout – In large facilities, a lot of time can be wasted getting from place to place. Try to arrange a route through the facility that avoids doubling back too much. Multi-floor buildings are best done floor-by-floor from the top down if possible. Inspections of large open buildings such as warehouses and shipping facilities are easiest if the perimeter is done first followed by the interior. In general, after considering the above mentioned criteria, the best place to start any electrical inspection is at the service entrance(s) and main switchgear(s) and then move on to the sub-panels.
Equipment Prioritization – It is always advisable to inspect all of your equipment, but occasionally budgetary or time constraints may require a prioritization paradigm. In these situations, an advance consult with your infrared professional can be extremely beneficial. Aside from site-specific equipment critical to production, a general priority list would be:
Substation (if applicable)
Service Entrance to Building(s)
High Voltage Transformers
High Voltage Switchgear (if applicable)
Emergency Generator Switchgear and Auto Transfer Switches
Main Switchboards/Distribution Panels
Bus Ducts, Wireways, and Wire Troughs
Motor Control Centers
Sub-Panels
Control Panels
Low Voltage Transformers
Contactors
Service Disconnects
METHODOLOGIES FOR SPECIFIC TYPES OF EQUIPMENT
Some types of electrical equipment can pose challenges to infrared inspection. The first challenge to be met is of course, safety. A complete, accurate, and effective infrared inspection requires that panels and equipment be opened while energized and under load to expose termination and contact points. Always follow all recommended and required safety procedures. Some panels and switchgear, by design, cannot be opened while energized. In these situations, smaller switches and control panels can sometimes be de energized, opened, and re-energized while open to permit infrared inspection. In some cases, especially if the load has been large and constant prior to opening, an infrared examination can detect anomalies without re energizing the equipment if performed before the equipment has a chance to cool.
Infrared Inspection Viewports – For equipment over 480 volts, panels that are infrared-inspected frequently, and panels that are large or extremely difficult or unsafe to open, viewports can be installed that allow for easy, quick, and safe infrared inspection. Consult with your electrical contractor, supplier, infrared contractor or consultant.
Outdoor Equipment – As mentioned above, outdoor equipment is best inspected on overcast days or as early in the day as possible for maximum accuracy.
Main Switchboards/Distribution Panels – As well as inspecting fuse clips and breaker terminals, rear and/or side panels should also be removed if possible. This allows inspection of internal bus bars, wire connections, heaters, etc.
Overhead Bus Ducts – Overhead bus ducts and bus-mounted equipment are often critical to facility operation and always difficult to inspect. The most efficient method is to first make an infrared inspection from floor level, noting any anomalies in the bus and bus-mounted equipment. Disconnects showing anomalous surface temperatures can then be singled out for further infrared analysis or repair.
SITE SPECIFIC RECOMMENDATIONS
Remember the following points to increase the effectiveness of an infrared inspection in various facilities.
Hospitals – There are several considerations unique to infrared inspections in hospitals; Back-up power supply is critical in hospitals. All primary automatic transfer switches should be inspected under both normal and emergency generator supply.
Hospital inspections are best performed in warm weather when cooling demand is greatest. Qualified personnel should be on hand to power up and test backup chillers and their associated equipment. In addition, if possible, a winter inspection of electric heating systems is also wise. Surgical suites often pose challenges. This is one instance in which the infrared inspection will probably be conducted under minimal load conditions. Coordination with surgical unit staff will be necessary. Many hospitals have medical office buildings attached. It is always advisable to make the effort of coordinating with the individual tenants in advance to facilitate inspection of panels in their offices.
Hotels – Thoughtful planning of a hotel inspection will help save time and ensure accurate results. ∙ In large hotels with extensive common areas, HVAC is of prime concern. As with hospitals, it will be best to perform the infrared inspection during warm weather. As mentioned above, panels feeding guest rooms are best inspected in the evening hours when most are occupied. Large kitchens should be inspected early in the day when most cooking is done and kitchen loads are at their highest. Remember to coordinate with elevator contractors if necessary.
Server Farms/Switching Centers, Airport, Broadcast, and Emergency Services Critical Power – These facilities present another instance when the infrared inspection is performed during minimal loads (usually 3rd shift). This is done to limit the impact of an accidental power interruption. These are also instances where transfer switches and their associated switchgear should be inspected under both normal and emergency supply, whenever possible. Advance consultation with your infrared professional is highly advisable in these situations.
SUMMATION
Implementing the discussed methods and adapting them to your unique situation will improve the efficiency and accuracy of your infrared electrical inspection, giving you the best returns on your time and money and ensuring maximum energy cost savings, safety, and loss prevention.
ABOUT THE AUTHOR
Bob is a Level II thermographer and has 19 years experience in the field.