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How to Perform a Quantity Takeoff for Electrical
Chapter 3

How to Perform a Quantity Takeoff for Electrical

In order to accurately estimate an electrical project, you need to understand how to perform a construction takeoff, and more specifically, how to establish the full scope of work required by means of a quantity takeoff

In the last chapter, we reviewed the importance of drawings and specifications. Now you’re ready to determine your break even cost to complete that scope of work and fulfill your contractual obligations, should you be awarded the project.

This involves the process of carefully reviewing the drawings outlined previously and performing a construction takeoff as outlined below. If you’re new to construction estimating or have followed the “eyeball” method in the past and do not know what exactly an electrical quantity takeoff around construction estimating entails, don’t worry—in this chapter we’ll tell you what you need to know to perform an accurate takeoff.

The quantity takeoff is the process of breaking down the drawings into predefined tasks or activities and quantifying the number of each based on the plans.

Tasks are actual units of work to be performed, such as “Install commercial grade duplex receptacle,” depicted on the plans using common electrical symbols, and detailed in the plan legend in combination with the specifications of the construction project that are usually provided by a general contractor.

You’ll use these counts and measurements to determine your material quantity and labor units for each task in your material takeoff, which is the starting point to creating an accurate estimate and building a profitable project.

Depending on the tools available, your construction takeoff can be done with a highlighter, hand counter, and digital measuring wheel using the manual takeoff method. Or, you can acquire a cloud-based software product that allows you to quickly bid, win projects, and manage workflow, such as our takeoff software, Esticom.

Either way, you’ll begin by choosing a single task to start with. For example, with a 2’ x 4’ light fixture you’ll highlight each light fixture on the drawing while counting with the hand tally. You can go through the plans clockwise or counter clockwise, it doesn’t matter which way, but be consistent and make sure you capture each symbol depicted on the drawing.

Once you’ve taken off all items for the page, notate the task and quantity clearly on the page and move to your next task until you’ve covered everything on the sheet. Then move to the next sheet in the plan set until you’ve completed all the quantity takeoffs.

As a best practice, you’ll want to create task totals on each page, and then summarize the totals on a quantity takeoff form, usually in excel format (or the last page of the plans if you’re completing it long hand). One benefit of takeoff software is that it will automatically keep track of your counts and allow you to filter by sheet and summarize the totals. If you’re using integrated on-screen takeoff and estimating software that is all in-one like Esticom, you don’t have to move quantity takeoff data from takeoff software to an excel spreadsheet and because it’s cloud-based, you can access it anywhere, anytime, from any device. This allows you to complete the cost estimating process in less time.

Common electrical tasks, such as a duplex receptacle, have many parts. This means it’s more effective to count items as assemblies versus individual parts and then break down to required parts later when you build a bill of material. For those with estimating software, you can build these assemblies ahead of time to streamline the construction takeoff process and adjust based on project conditions.

electrical estimating tip

Tip from the Pros

Electrical Estimating and Takeoff software can keep track of your counts automatically by performing a digital takeoff and utilizing pre-built assemblies that calculate your material totals, saving you hours of manual calculations. In addition, many takeoff software applications like Esticom have a symbol recognition tool that not only acts as a digital takeoff but will automatically count symbols on a set of plans saving you even more time by reducing the time-consuming process of manually counting each symbol.

For tasks such as conduit runs for branch circuits and feeders, you’ll need to capture the linear footage totals using a digital measuring wheel or construction takeoff software with a built-in measuring capability. We suggest taking off your conduit runs by wire count as separate takeoffs, so for example measure all of your runs with three wires and write down the total length in linear feet, then measure the five wire runs and so forth. Once you’ve completed each you can multiply the linear footage by the wire count to get your total wire quantity for the task, so for example (1,200) feet 3/4″ overhead branch with 3 #12 wires would require (3,600) feet of #12 wire. This also allows you to adjust the labor difficulty for the task for improved efficiency – generally as the wire count increases the labor unit per wire will decrease due to the efficiency gained by pulling multiple wires at once.

It’s important that you adjust whatever tool you use for the denoted plan scale; i.e., 1/8” = 1’ and confirm it’s accurate on a page per page basis as it changes. On “typical drawings” you’ll sometimes have multiple scales for the same sheet. The scale denoted on the drawing can be incorrect if the plans were printed in the wrong format, the drawing was scanned, or a multitude of other reasons. Ultimately, it’s up to you to confirm the accuracy of the scale and ensure you have accurate takeoff quantities.

Scaling can be done with your measuring wheel and most construction takeoff software packages by measuring a known distance, such as a doorway, and entering the distance to calibrate the drawing to an accurate scale. It’s always a best practice to use the longest distance available and verify horizontally and vertically on the page as the drawings can be skewed.

Start with Lighting

One strategy for starting a quantity takeoff recommends following the same order that the work would progress. However, this is often impractical as it’s difficult to lay out items like conduit, wire, etc., without first being familiar with lighting, devices, gear and panel locations.

A better way to start is by beginning with lighting to get familiar with the project. As you perform the counts, you’ll inherently review the drawings and gain a better understanding of the layout of floors, sub-systems, conduit pathways, etc.

Find an open work area with plenty of light, a set of highlighters, hand counter and a digital scale master for taking linear measurements. Locate your plans lighting drawings to start and follow the sequence below:

electrical estimating tip

Tips From the Pros

It’s not required to describe the fixture by manufacturer, catalog numbers, or color. Not only is this time-consuming, the lighting supply firm will do this for you per the plans and specifications. You should identify these per the fixture type; i.e., Type A, Type B, etc. and count quantities of each. Remember, you’ll still need to account for labor cost and need to notate the type of fixture.

As an added benefit with electrical estimating: it’s common practice to send light fixture counts off to the respective suppliers for project pricing. This can take time and is largely out of your control, so getting your light fixture counts first is a best practice as you get your supplier working on pricing while you finish the rest of your construction takeoff. This usually includes consumables and items that can be priced based on past purchase history.

It’s also effective to break out your quantity takeoff by phase. This does a couple of things. First, it makes it easier to spot a mistake. You can look at the tasks in smaller chunks and have someone else double check your counts as you go. Once the project is awarded, this also helps to build a work breakdown structure for project management purposes that you can use for ordering materials, scheduling resources, and creating project budgets for cost control.

Always Have a Fresh Set of Eyes Double Check Your Construction Takeoff

Before moving to the process of pricing your estimate, we suggest having a counterpart review your counts to make sure you didn’t miss anything. A fresh set of eyes always finds a few things you overlooked and can provide some perspective on the installation you might not have considered.

Always Have a Fresh Set of Eyes Double Check Your Construction Takeoff
electrical estimating tip

Tips from the Pros

Create a color scheme for each system; i.e., green for lighting fixtures, blue for panels & gear, pink for devices—and make sure your team follows the standard for all projects.

Transfer Your Construction Takeoff Quantities to Estimating

Now that you’ve completed your construction takeoff and had a counterpart double check your counts, you need to move the quantities to a clean quantity takeoff sheet. Depending on the resources available, this can be a pre-printed quantity takeoff form, an excel spreadsheet, or, if you’re using takeoff software, it should push the quantities to an estimating module to begin the rest of the estimating process.

Experience Matters in Construction Takeoffs for Electrical Estimates

The “quantity takeoff” process itself is simple, but it requires a solid understanding of electrical installation methods, codes, and general construction industry experience to understand working heights, elevations, etc. We don’t recommend delegating this out to someone with less experience with the belief that they’re just “counting” symbols while you double check their work to save time. That is a recipe for disaster.

While inexperienced personnel can surely count symbols on a plan, they will often not understand the difficulty of tasks or how the various systems relate to one another. More importantly, if you delegate the takeoff to someone else, you miss the opportunity to become familiarized with the project, which will lead to errors, omissions, and, ultimately, an unprofitable project.

Now that we’ve gotten that disclaimer out of the way, let’s move on to electrical cost estimate types.

Continue to Chapter 4

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