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Article # 0044

In-House vs. Contractor Considerations for GPS Based Field Inventories on Electric Distribution Systems

Kevin Perry, PE

Background and Overview

Prior to the personal computer many electric utility mapping and plant records were managed with large hard copy books and storage rooms full of file cabinets.  With the advent of the digital age these treasuries of data began slowly making their way into bits and bytes.  The realization that much of what was stored was geographically and quantitatively incorrect became a very common reaction to the process of "going digital".

In the last twenty years many companies have sought to correct the inaccuracies through field inventories and verification counts.  One problem with these inventories was the poor quality of the underlying base map.  Many of them came from county section, township, and range maps that themselves were incorrect by hundreds, if not thousands, of feet in some places.  Other base maps had been hand drawn based on a road or USGS map and then manually updated as new plant was added.  These methods really did not cause a problem as the maps were seldom compared to any other sources and were used only as referential and not exact placements.

Unfortunately, verifying the location of a particular facility on an inaccurate base map only corrected the quantities and many times compounded the spatial errors.  With the arrival of public global positioning satellite (GPS) information the flaws in maps from all entities became glaringly apparent.  Today the equipment for GPS locations is relatively inexpensive and the level of accuracy is high.  To address a myriad of problems associated with inter-entity cooperation many companies are now redoing their inventories and requiring their employees or the contractors doing the work to provide GPS accurate locations for all facilities inventoried.

If a particular company has made the decision to do a GPS based inventory the question of whether to do it with in-house personnel or hire a contractor will be one of the first decisions.  This paper will seek to outline some of the considerations that electrical distribution companies should complete before choosing to do the work themselves or hire a contractor.

Inventorying an electric system is not rocket science but it does require a solid understanding of the facilities being collected and attention to detail.  GPS position acquisition is not rocket science either but it requires a solid understanding of the GPS equipment being used and the proper methods for spatial adjustments and accuracy verification.

Contemplating In-House Projects

Company employees will excel at recognizing the facilities and understanding the connectivity of the system and can successfully perform a field inventory as long as they are properly trained in the use of the equipment.  Some of the common pitfalls in using in-house personnel are actually unrelated to the difficulty of GPS software and equipment.  Ask some of these questions when considering using in-house resources:

    How long do we want the project last?  Stretching out the project will make the impact on the expense sheet more palatable but  projects that run too long run afoul of the changing nature of an electric distribution system and will heavily complicate the collection process.

    Is our company committed to letting the assigned employees focus on the inventory or will they be expected to work it around their normal duties?  If you have employees that have some available time between duties it may be attractive to utilize them and avoid hiring or contracting but constantly starting and having to pull off to address daily operations will wreak havoc with the timeliness and accuracy of the inventory.

    Are we going to need GPS trained employees for the ongoing addition of plant and maintenance on the GIS system?  If you anticipate hiring new employees or changing the responsibilities of specific employees to input new data and correct flawed information as it is revealed then it might make sense to use the inventory process to train the employees.

    Will we be buying our own GPS equipment and will it be of sufficient accuracy to collect the data?  GPS equipment can cost a few hundred dollars up to many thousands of dollars depending on the level of accuracy you have chosen to require.  The method you will be using for adding new plant to the GIS will play heavily here.  If you have a lot of work and plan on using your GPS equipment in the design stages then you are committed to purchase equipment capable of meeting your specification on accuracy.  If you choose to collect it after completion the option of having a contractor come in on a monthly or quarterly basis and catch up the GIS can be attractive.

    Have we shown the ability to stay focused on special projects in the past?  Face this one honestly and decide if you want to follow past success, correct past practice, or choose a different route.

    What are the anticipated savings or extra expenses and are they worth it?  The unique situation of your company will determine whether you think you will save money or actually have to spend more than hiring a contractor.  Make sure pros and cons are compared to the monetary value.

Contemplating Using a Contractor

Contractors have been used extensively by electric distribution companies and may be well suited to your project.  Some considerations and research will definitely be worth your time prior to contacting contractors so think through the following with your staff:

    How long do we want the project to last?  The contractors' rates can be significantly different depending on what timetable you specify and can swing either way based on the market at the time of your inventory.  If you can be flexible within a broad window then more contractors will be interested in your work.

    How will this affect relations with our bargaining unit?  Although GPS work generally does not require any association with your facilities beyond what a pedestrian observer has the freedom to do this question is best handled beforehand.

    What level of oversight are we prepared to provide?  This will be of special interest to the prospective vendors.  An excessive amount of administrative overhead will quickly drive up the cost but a lack of assistance to the contractor can also adversely affect your cost and quality of data.  An experienced contractor will want a commitment, sometimes even contractually, of company personnel and response time if they are to meet your schedule.

    What are the specifications on the project?  The more technical you require the contractor to be the fewer you will have to choose from and the higher the cost.  Many of the attributes you would like to have collected can be populated in mass by in-house personnel after the contractor finishes.  Wire size is of special interest.  Accurately judging sizes from the ground can be tough even for your own employees.  You will want to agree before contacting prospects on just how strict you plan to be.

    Do we really want to require insurance and bonding similar to what we require from line construction contractors?  This might even require special permission from your own superiors.  Keep in mind that contractor personnel will usually not be doing anything that the public can't do.  There are many smaller companies who can offer excellent quality and very reasonable pricing but may not be able to quote because of major overkill in your bonding and insurance requirements.

    Have we planned to proactively notify our customers that they will be seeing the contractors on our system and have we established procedures for dealing with accidents, complaints, and calls to the local authorities?  This will eventually have to be addressed and is much more pleasant when done beforehand.

    Should we buy the GPS equipment or have the contractor supply it?  Depending on the size and, more importantly, the length of your project you may want to work out an arrangement to purchase the equipment, have the contractor use it for the project, and then use it in-house once the project is done.  You will essentially pay for it either way but you could end up getting some very inexpensive training if you're willing to be creative.

Final Comments

There is an endless list of details that could be addressed but quite often the technical details overshadow the big picture considerations.  If you think you want to go in-house contact some similar electric distributors who have done it themselves.  If you are leaning towards a contractor do the same.  In either case have your employees take the time to visit with those companies and develop a list of questions and possible pitfalls to be avoided before you begin your own work or get embroiled in sales pitch, promise everything meetings.


Kevin Perry is a registered professional engineer in the states of Georgia and Alabama.  He obtained a Bachelors of Electrical Engineering from Auburn University and worked for over ten years in engineering departments with electrical distributors before moving into utility GIS software development and implementations with a leading vendor.  He now does free lance engineering work with distributors and vendors from his home in Madison, AL.

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