For branch takeoff, measuring all of those little lines can really be a pain in the neck. It’s time-consuming and mind-numbing, especially on large projects. What a drag. Sometimes I’d rather be cleaning toilets. If you haven’t already guessed, measuring branch is my least favorite part of performing a takeoff.
The only good thing about measuring branch is you do not have to be extremely precise. It’s sort of like that old saying, “Close only counts in horseshoes and hand grenades.” If you are off by a foot here and there, the impact on your estimate is minimal. It does matter that you comply with the specifications and use the required materials in each location. It doesn’t matter much if you don’t get the right support materials for every installation. Your installers will probably use something else anyway, as most electricians have a favorite way of doing things.
The preceding is how my employers and teachers taught me to takeoff branch. There are those who disagree with me regarding branch takeoff, so I use more detail when I am working for them. However, most of my customers do not want me to spend an excessive amount of time on it. When it comes to feeder takeoff, though, it’s a completely different story.
Generally, branch is defined as conduits up to and including 1 inch. Feeders include all conduits larger than 1 inch.
Feeder takeoff requires precision because of how much these conduits cost. Most often, the cost of a branch-conduit installation is just a few dollars per foot. On the other hand, feeders can cost hundreds of dollars per foot to furnish and install. All feeders, whether underground or overhead, need to be carefully measured, with all supports and accessories well detailed. In addition, the scale needs to be calibrated, not set. Setting the scale is no longer adequate, as many plans—paper and digital—are no longer true to the stated scale. Most electronic scalers and on-screen estimating programs have the ability to calibrate a drawing instead of selecting a scale.
Of course, there is more than one way to takeoff feeders. The first choice you may have to make is your takeoff method: listing or direct input to a computer estimating system.
If you are still estimating without a computer system, you will have to start with the listing method: The first step is to copy information from the plans to a feeder listing or takeoff form. Only preliminary information is entered at this time, including where the conduit comes from, where it goes to, size and wire fill.
Once all of the feeders are listed, it is time to measure them. When all of the feeders are measured, the takeoff is broken down into its component parts. The parts are then transferred to a paper pricing sheet where each part is priced, labored and totaled.
The fastest way to do feeder takeoff is to enter them directly into an estimating system, skipping the paper listing step. Each estimating system will handle this task in its own way, so ensure you understand the way your system works. These systems use a number of different methods, including prompting and assemblies. Personally, I prefer to select and enter each component manually, because it gives me the most control over each feeder’s content. Since feeders are expensive, I don’t want any inexact components in my takeoff.
Now for the actual takeoff. First, your length measurement must be precise. We usually measure at right angles to the building lines and then add for the ups and downs. I always review the architectural elevation drawings before starting my measurements so that I know what the actual ups and downs will be.
Also, ensure your measurement does not go through areas such as elevator shafts, stairwells and other locations where they’re not allowed. Most specifications do not allow more than 270 degrees of turns in any single conduit run, so be sure to add pull boxes where they are needed. For most projects, we round up our measurements to the nearest 5 feet. This covers waste and the fact that you can’t purchase partial lengths of conduit.
Finally, don’t forget to add makeup to your wire. A good rule of thumb is to add 5 feet for small termination points, such as a panelboard, and 10 feet for larger terminations, such as a switchboard.
Feeder systems can get very complicated. It is beneficial on many projects to actually lay out the feeder routing and support system while preparing an estimate. Electrical contractors who bid on the largest of projects often do a computerized 3-D layout before completing the estimate. This ensures the feeders can actually be installed as estimated.