Let’s get into more detail about one of the bigger estimating puzzles I have encountered in recent years.
Last month, I suggested you list upsized branch in a feeder schedule. It turns out that many estimators do not know about feeder schedules. For all of you in that category, let me introduce you to them. As a NECA-trained estimator, I was introduced to feeder schedules early in my career. Why we used them was never explained—it was just the way things were done. However, it did not take long to discover why they were used.
I was running behind on a project, so I decided to skip the listing process and take off each feeder when I found it on the power plans. That turned out to be a slower way of taking off feeders. First, it depended on the feeders being shown on the plans, which does not always happen. Then, I had to spend extra time making sure that all the feeders indicated on the single line showed up on the floor plans. Finally, there was too much time expended flipping back and forth between various plan sheets.
So, what is a feeder schedule? Before computers, it was an 8½-by-11-inch piece of paper, with 13 columns and as many rows as could fit on the page. The column headers, left to right, were: Feeder Number, Conduit Type, From, To, Conduit Size, Length, Ells, Terminations, Bends, Number of Wires, Wire Size, Length and three miscellaneous columns. You can see it on this page, and I posted a scan on my blog at https://electricalestimator.wordpress.com/2020/11/03/feeder-schedule.
Of course, being a bit of a techie, I converted the form to a spreadsheet as soon as I could. This allowed me to customize the form as needed to meet changes in the industry and the type of work I was bidding. You can tell how old this form is, as it does not even have a column for a ground wire.
The listing part of the process consisted of filling in the columns for From, To, Conduit Size, Number of Wires and Wire Size. Once the listing was complete, it was time to go measure the conduit and fill in the rest of the columns. We referred to this part of the process as the takeoff.
After the takeoff was finished, the totals for all the components were transferred to a price sheet for pricing and labor. Fast-forward from 1980 to 2020. Most estimators are using computer-based electrical estimating systems. (If you are not, we need to talk.) For those of you using estimating software, check with your vendor, as your software may have a special way of handling feeders, making the process of taking off feeders easier.
Back to the original reason for mentioning feeder schedules: upsized branch. There are three parts to my definition of upsized branch: any branch conduit that has more than two conductors plus a ground, the wire size is larger than #12 and the wire size is not specified on the power or lighting plans. Never assume that any unmarked branch is 2 #12 and 1 #12 ground, even if that is what the symbol list indicates! Upsized branch must be identified and dealt with before measuring the rest of the branch.
I study several sources of information to find upsized branch. The first is the panel schedules. Find any circuit breaker larger than a 20A two-pole. When you find one, list the branch on your schedule. For instance, when you find a 30A three-pole, enter the branch for this circuit on your upsized branch schedule. What size is the wire for your 30A three-pole breaker? You can go with the National Electrical Code requirements. However, you should check for other requirements on the plans. The wire sizes may be shown in the panel schedules, or in a table indicating what size wire to use with each amperage. They may also be shown in an equipment schedule.
1. Identify and list the upsized branch on a schedule
2. Takeoff the upsized branch in the schedule
3. Takeoff the balance of the branch on the plans
In terms of estimating time, upsized branch is one of the more time-consuming changes to the way electrical plans are engineered today. In other words, the designers save time preparing the plans, and the estimators are required to spend more time taking off the plans. This is a good argument for averaging branch instead of measuring it.