While CAD drafting systems are an increasing part of the building process, many electrical contractors face choices between investing in CAD, or a raster system with software links to CAD, or watching the process from the sidelines. In the meantime, software manufacturers are seeking solutions to help electrical contractors work with the CAD drawings of architects and engineers, digital raster files, or to use CAD in their own project management.

CAD systems (once known as CADD and short for Computer Aided Drafting and Design) allow an engineer or contractor to create project drawings on the computer, view a design from any angle and to zoom in or out for close-ups and long-distance views. In addition, the computer can keep track so that when the contractor changes one detail, all other details that depend on it are automatically changed as well.

Until the mid-1980s, all CAD systems were specially constructed computers. Now, you can buy CAD software that runs on general-purpose workstations and computers.

For electricians, CAD systems offer the ability to perform estimates of conduits, outlets and switches with a fraction of the labor time they would need for manual estimates. With CAD software, symbols and other graphics define the details of a job. Those details can then be linked to a PC with an estimator database where the symbols are counted or lengths are measured and electrical contractors can calculate the resulting material and labor. What would take hours on paper can be done in a fraction of the time with some initial keyboard strokes. However, while CAD systems make the estimating process easier for electricians, and several systems are specific to electrical work, many electrical contractors still do without.

There are several good reasons for that reluctance. CAD and AutoCAD by themselves can be confusing and inadequate for electricians and the use of CAD generally requires a one-week training course and further investment into software add-ons. By itself there is nothing electrical about CAD software. To make it work for them, electrical contractors must add industry-specific functionality. But with that electrical-based modification, CAD systems can be used for layouts of electrical or power distribution as well as the smaller details of a project.

Most expect CAD software systems to be more prevalent with electrical contractors in the coming years. Along with upgrades in CAD itself, emerging third-party CAD applications—known as “Cadd-ons” by those in the industry—allow contractors to calculate just about anything while eliminating the need for paper drawings.


CAD drawings are typically stored using the AutoCAD drawing file format known as a .DWG file. According to Keith Hallman, manager of CAD Integration Products, a new division of SELLECT (which was recently purchased by Accubid), at least 90 percent of all legacy CAD drawings are stored as AutoCAD .DWG files. Because AutoCAD dominates this market, users need import/export software for any other proprietary vector format.

On the other hand, digital cameras and scanners are contributing to the growing popularity of raster formats such as .JPGs and .TIFs. Raster-based file formats can display scanned images and digital photos, while vector-based formats are the better choice when defining shapes and objects on a picture. Raster formats are known for effectively and realistically conveying shades and tones.

Raster graphics are made up of pixels or dots. The resolution of a raster-based graphic, which is measured in dots per inch or DPI, is set when the image is created. That means the quality of the image is affected at different sizes. In addition, raster images are often limited to their original size and resolution setting. General and electrical contractors often work with digital photos and scanned blueprints and then seek to convert raster bitmaps to vector formats. This conversion is not as simple as it sounds. While contractors may save money with some less expensive conversion processes, the cheaper the software, the poorer the resulting file quality and value.

For electrical contractors, this means making a choice to invest in AutoCAD and the software that will allow them to translate a raster file from a scanned or digital image into a workable vector, or CAD file.


But is all this software necessary? The answer sometimes depends on which electrical contractor you ask. The variation in availability of CAD files during estimating leads to a very different experience for different electrical contractors.

Design/bid/build contractors are often those most familiar with estimating software. They generally have the advantage of access to the architect’s blueprints and CAD drawings before being awarded a contract. The less fortunate majority must create estimates using only the blueprints, working either manually or scanning them after being awarded the contract. But even these contractors may benefit from a CAD system. While electrical contractor bidders cannot expect access to the architect’s CAD files, often they can secure access at the contract award phase. However these CAD files are obtained, contractors with CAD still have the advantage of being able to prepare a very specific estimate in less time or the advantage of better project management.


One goal for manufacturers is creating a better automatic vectorization process—the automated use of raster-tracing software to create a vector file that can be used with CAD software. While automatic vectorizing is available, it doesn’t offer the contractor a decent substitute for a full-featured conversion. Although it bills itself as automatic, it requires substantial, labor-intensive cleanup.

SELLECT offers a software system specifically for electrical contractors called cadTakeOff. This software allows the contractor to link his CAD drawings to any participating estimating vendor, as well as spreadsheets or other in-house programs. With cadTakeOff, CAD drawing files received from any client or associate can be processed through the electrical contractor’s estimating software to create cost reports. The company also works exclusively with electrical contractors to sell, support, train and develop CAD systems for the contractor’s needs.

Following the acquisition of SELLECT by Accubid, Hallman, who is manager of Accubid’s new CAD Integration Products division there as well as SELLECT’s founder, promised an “even more robust product in place by the NECA show.” Hallman offers technical workshops and presentations to electrical contractors in the effort to help the electrical industry see the way CAD can benefit them.

Hallman said SELLECT Accubid is also looking into addressing the issue of vectorization. “That’s a big carrot for the programming community,” Hallman said. “So far there’s just been improvement on what’s already been tried before.”

According to Hallman, some contractors enjoy access to CAD files because of a strong relationship with the architect or engineer, regional trends, or value marketed to (or realized by) the owner/developer.

Hallman said one common question he hears goes this way: “We get a lot of drawings e-mailed to us. What tools can you provide us with to estimate them?”

“We caution the caller that just because the data is available electronically does not mean it’s in vector format. We then encourage the contractor to do the homework of asking if there is access to the actual CAD files, and if not, to consider ... ways to obtain such access,” Hallman said. He warned that contractors who are offered electronic versions of drawings may assume the files are CAD when they may actually be a raster image.

“A sometimes-suggested workaround is to simply obtain a view-only (raster) format from the CAD author,” Hallman said. “In theory, it would then be possible to perform semi-automated takeoff using raster-based quantification tools.” However, because raster files contain no intelligence, the raster application software must be programmed to provide the accuracy required by estimators.

“The world sees raster as a potential solution,” Hallman said. “If you don’t have access to the CAD file, you can (later) put it through a scanner.” He added that, “We have kept our finger on the pulse, working with the raster industry,” despite the fact that what everyone wants isn’t there yet. Hallman pointed out that, “People not being familiar with raster have hope that it has no constraints. But it does.”


In the meantime, upgrades continue and most software providers offer training in class or on location. Recently, AutoDesk released a new version of AutoCAD 2005 to replace the 2004 version.

McCormick Systems Inc. offers a new version of its software with some new features, said Ed Bundy, lead developer/president. The latest version allows contractors to divide a drawing into segments and estimate cost and needed material, for example, for a specific room within a project. “We’ve made it easier,” Bundy said. Contractors can now select a section of their drawing, and bring up specific details for that section.

But Bundy indicated electrical contractors have been the most reluctant to transition into this technology. “There is lots and lots of interest,” he said, “but there is a huge learning curve.”

Contractors often stand to save time with the software but will have to expend at least some time up front to educate themselves. While many take courses, a few successfully train themselves and their staff. McCormick offers training for its software while there are courses to assist with AutoCAD.

Some contractors are more active with their CAD software than others.

Jim Rowing of Mass Electric Construction Co. finds CAD helpful for “drawing lines and circles.” Mass Electric is involved in many design/build projects and uses Accubid for their estimating.

Terry Leptein, structural engineer for Kiewet, a large civil general contractor, says his biggest complaint about CAD, which he has been using for two decades, is the constant upgrades. “I wish they’d stop updating things,” he commented. “It gets to the point where everyone has to have the new car on the block to drive down the street.”

Despite that concern, keeping up to date with CAD and its upgrades is likely to become an increasing necessity for many contractors. Getting the needed education, through manufacturer training programs and symposiums may be the best way for contractors to ensure they have invested in the software that will be cost-effective. EC

SWEDBERG is a freelance writer based in western Washington. She can be reached at claire_swedberg@msn.com.