We're all familiar with two dimensional design drawings — not to mention the questions that usually accompany them because they can provide only so much information before becoming hopelessly cluttered. While traditional drawings are very useful, they can easily fall short when used for a complex electrical distribution system. Sometimes, their limitations even distort or understate the scope of work for commercial or industrial electrical projects. This is where three-dimensional computer-aided design (3D CAD) modeling comes in. As the complexity of a given electrical system increases, the benefits of 3D CAD modeling become more compelling.

Seeing before believing. Of course, seeing the electrical system represented in 3D will help you understand it better, but the benefits go far beyond that. Being able to see the project in three dimensions ahead of time produces benefits, such as:

  • Coordination

    The mechanical, electrical, and plumbing (MEP) systems often conflict with each other — yet nobody seems able to address these conflicts until some serious labor hours have been spent. With 3D CAD, the design team(s) can easily explore and coordinate complex topics and interactions between systems during the design phase — rather than trying to solve conflicts only after they become apparent in the field. It's faster and cheaper to design conflicts out than to fix them later. A simple raceway routing conflict with plumbing, for example, may take a crew of six two days to fix. If only the designers could have visualized these runs ahead of time, right?

  • Scope clarity

    The 3D CAD features of the drawing significantly improve the ability of the entire MEP design team to comprehend the scope of electrical equipment and services. Complicated routing schemes going both horizontally and vertically can be difficult to explain to others (e.g., architects or owner representatives). A 3D model can make the design intent clear — going back to the old adage, “A picture is worth 1,000 words.”

  • Field efficiency

    With 3D drawings, the field electrician can more efficiently construct the electrical system on site. You can accurately determine the number of bends and pull boxes needed to complete the installation. You can detail and illustrate the elevations of multiple overhead runs, and clearly show penetrations into equipment and vaults.

  • Value engineering

    Have you ever been frustrated when trying to explain value engineering options to the owner? You know from experience that a small additional investment can result in a more robust or reliable electrical distribution system while improving life cycle cost and energy savings. With 3D CAD, you can show rather than tell — and be far more persuasive. That means a better project all around and a happier client.

  • Changeorder prevention

    You know the pain of changeorders and the hassle of responding to requests for information (RFIs) during construction. Using 3D CAD can prevent most of both. This means more value to the owner and greater efficiency for you.

  • Better estimates

    With 3D CAD modeling, you can virtually “lay out” the entire electrical system — that is, you can route it, “install” the pull boxes and fittings needed for the job, and “bend” the raceways. The drawing can give you summary totals of each part number needed and each bend to be made, which dramatically improves the accuracy of your estimate.

Documentation. Most owners and general contractors expect comprehensive instructions detailing proper operating and maintenance procedures for their electrical systems. If you've produced this documentation as a separate step after the work is done, you've headed down the road to inefficiency. And because of the time crunch, you've probably not done your best work.

With 3D CAD and building information modeling (BIM), you can implement this documentation into the drawings, including such things as notes on which equipment needs infrared testing or other maintenance and when to schedule the various procedures for each piece of equipment. Doing this as you go increases the accuracy of the documentation while decreasing the cost of producing it.

Remember, the 3D drawing exists not on paper but in electronic layers. Therefore, you can pack a huge amount of information into one drawing, organize it well, and still have an uncluttered drawing. A set of 3D CAD drawings can become a “live” document and a core asset in facility management. For an example of a 3D CAD drawing, which details the electrical service main distribution system and a standby diesel generator system of a recently completed SASCO design/build project, see Diagrams 1, on page C34, and 2, above, which shows the same drawing from another angle.

Beyond 3D. The next step in the evolution of this enhanced design and construction process is the development of 4D CAD and BIM.

Basically, 4D CAD tools incorporate time and project scheduling into the 3D CAD drawings. The owner and design team can watch the virtual construction of the project. Through the 4D animation process, you can test different construction sequences to minimize conflict between trades, help find the critical paths, and reduce total construction cost.

BIM is a new approach to the design and construction process. The information you can implement into this modeling includes scope, schedule, and cost. You can use BIM to look at several design options to find the most effective path in the design. This process can allow you to insert data about the electrical equipment into the drawing. Information on the use and performance of the building can be readily available to anyone who calls up the drawing. It's also possible to keep a digital record of the electrical changes and tenant improvements — right in the drawings.

Going forward. The construction industry is catching up with the automotive industry with respect to the implementation of these sophisticated digital modeling tools. Mass production has made the transition much more cost effective in the automotive world. As this new technology is becoming more readily available to the engineering community, construction teams increasingly understand the life cycle benefits, making 3D modeling and BIM more commonplace.

The computer requirements for running these 3D and 4D CAD applications and the BIM used to be “high end” and almost prohibitively expensive. Now, even a mid-range consumer-level computer with as little as 1 GB of RAM can run these applications with adequate speed for the typical project — but moving up to a fully equipped engineering workstation is usually worth the money because of faster renderings. Of course, as the complexity increases, so do the computing requirements. But typically, hardware is not a barrier to moving forward with a 3D CAD system.

The most common barrier to engaging in 3D CAD is the lack of the ability to use the software. The learning curve for 3D CAD is a bit steep, but there are good programs and books to help a person proficient in traditional CAD gain the needed skills. Investing the time and money into the necessary training requires a commitment, but that's true of any other skill you rely on to bring projects to a successful conclusion. The ability to competently perform 3D CAD modeling is what can elevate an average electrical contractor into a key MEP team member.

Are you ready for 3D CAD? The answer may depend on whether you are tired of the limitations of CAD or on whether or not you want to elevate your services and become that key design/build team member. Some of the more leading-edge electrical contractors have already implemented such 3D CAD systems in a continuing effort to evolve and stay ahead of the curve. Increasingly, owners and general contractors are making 3D CAD one of the project requirements. You've just gotten a glimpse of some of the reasons why.

Lane is a registered P.E., RCDD/NTS specialist, TPM, LC, LEED A.P. and serves as director/vice president — engineering for SASCO Design/Build Electrical Contractors and Consultants in Woodinville, Wash.