When we left off our last column in February, we were in the middle of the itemized estimating take-off. This time, we'll finish with the take-off process, and take a look at the proper application of labor units. In case you missed the first part of the article, here's a brief summary of the first five steps in itemized estimating.

  1. Review the job you are about to estimate.

  2. Do a take-off on the lighting fixtures.

  3. Do a take-off on all the wiring devices.

  4. Do a take-off on the one-line diagram.

  5. Do a take-off on the branch circuitry, including raceways and wiring.

  6. Do a take-off of all the special systems. Most medium- to large-sized electrical installations will require one or more types of special electrical or electronic systems. The estimate will be required to include the cost of these systems, which include fire alarms, lightning protection, sound systems, closed-circuit TV and nurse-call systems.

    Special systems are usually handled in one of two ways:

    • The estimator does a complete take-off of all the individual items required by the special system, prices each item and when the time comes, the company's electricians will install the system.

    • The estimator reviews the special system(s) shown on the plans and then calls specialty contractors to get prices for the system(s) in question. The estimator reviews these prices, compares them with the plans and incorporates them into the final estimate. At the appropriate time, the specialty contractor will send workers to install the system and be responsible for its correct installation and acceptance by the owner.

  7. Write up the estimate. Your next job is to write on a pricing sheet all the quantities you have been keeping on separate sheets of paper. A typical pricing sheet is shown in Figure 1. On this sheet, you first write down the quantities of all the electrical materials that will be required for the installation. Then you fill in the appropriate material and labor prices for each item and extend these figures. When writing up EMT conduit, you can use the “quantity from a quantity” method to obtain the proper number of couplings (one coupling for every 10 ft of conduit) and straps (one strap for every 10 ft of conduit, rounded up a little bit).

  8. Finalize the estimate. This is the final step in preparing the itemized estimate. Review the plans and the estimate and pricing sheets, making sure that everything has been included. Next, take quotes from suppliers on materials (see Quote Sheet, Figure 2) that you cannot price. Most typically, these items are light fixtures, switchgear and special systems. After you receive and review these quotes, record them on a bid summary sheet, as shown in Figure 3. Record on the bid summary sheet on the line marked “miscellaneous materials” the total material price taken from the pricing sheets. Also record on the bid summary sheet the labor hour figures taken from the pricing sheets; multiply these by the average hourly labor rate to obtain a total cost of labor for the installation. Add all these items together with job costs, overhead and profit to get a final bid price. Job costs typically include the following:

    • Storage trailer rental and insurance

    • Equipment rental

    • Job site utilities

    • Blueprinting costs

    • Travel and lodging expenses

    • Performance bonds

    • Any other costs that will be incurred because of this project, but not included in the company's overhead

Applying labor units to the quantities of electrical materials shown on the pricing sheets is extremely important to the process of electrical estimating. The estimator must start with a good set of labor units and apply them according to the conditions of the job he or she is estimating. This requires some tempering of the labor units. For instance: If a certain project has an especially high ceiling, the estimator will have to raise the labor units for any equipment that must be installed on or above the ceiling. The tempering of the labor units is what makes an estimate accurate. Careful thought and experience are required to temper labor units well. All the labor units are shown as hours per each or hours per foot.

Reprinted with permission from NFPA Successful Electrical Contracting. Copyright 2001 National Fire Protection Association, Quincy, Mass., 02269. This reprinted material is not the referenced subject, which is represented only by the standard in its entirety. To purchase a copy of NFPA's Successful Electrical Contracting, go to NFPA's online catalog at www.nfpa.org.


  1. All pieces of equipment weighing more than 250 lbs. should be individually considered in assigning a labor unit. The estimator should mentally review the difficulty of putting the piece of equipment in place.

  2. When groups of feeders are run in parallel, the labor units for installing both conduit and wire can be reduced by up to 30%, because of the reduced set-up time for every run after the first.

  3. Labor units for feeder wire should be increased if the runs are exceptionally short, or decreased if the runs are exceptionally long. This is because of the ratio of set-up time to the number of feet in the run. A short feeder run requires virtually the same amount of setup time as does a long run.

  4. The estimator should remember that it is sometimes prudent to apply overhead and profit separately to very expensive items (most commonly generators or sub-contract work), as these items carry almost no risk, being primarily items simply bought and re-sold by the contractor. The percentages of overhead and profit can be lowered on these items.


E-MAIL YOUR NE CODE QUESTIONS TO MIKE AT: mharring@primediabusiness.com

Include a sketch where appropriate.