County justice center · 395 lines
Portable-generator connection
The takeoff carried a $440K generator and its pad, but not the 26 36 33 connection cabinet or the two 70A non-fused disconnects with interlock.
Makeoff data report · November 2026
What 67 Makeoff findings show about the scope between the generator quote and the takeoff, and a 13-point generator takeoff checklist to catch it.
Source: Makeoff production database · 40 projects, 16 electrical contractors · Apr 1 – Nov 3, 2026
Missing generator sets were the largest group of generator findings Makeoff raised: 27 of 67. Estimators we've talked to say some shops don't take off the generator on the first pass. They price it from a vendor quote and build the installation labor off that quote. This paper assumes that workflow and looks at the scope that lands on neither the generator quote nor the labor built from it: the feeders, the BACnet wiring, the ground rods, the sign at the service.
Between April 1 and November 3, 2026, Makeoff raised 67 unique missing-item findings tied to Section 26 32 13, Engine Generators. They span 40 projects from 16 electrical contractors and exclude existing and owner-furnished equipment. Setting the 27 generator sets aside leaves 40 findings.
Twenty of the 40 were feeders, control raceway, monitoring wiring, grounding, branch devices and labels at the generator. A generator quote doesn't include them, and labor built off the quote doesn't count them.
Fourteen findings named generator switchboards, connection cabinets, disconnects, annunciators or other accessories. Either vendor can carry them, so each can assume the other does. One contractor checked a remote-annunciator finding and marked it "this is a miss."
The installation findings total about $77K across the 11 with an estimate. None moves a bid on its own, and none shows up when labor is priced from a quote's equipment list. But the drawings and specs call for every one, so each miss comes out of the EC's margin.
Twenty-seven of the 67 findings flagged a generator set with no takeoff line. That many missing generators suggested a workflow, not 27 separate misses.
In our conversations with estimators, some told us they don't add the generator to the takeoff early. They price it from a vendor quote and build the installation labor off that quote later in the bid.
So this paper assumes that workflow. A missing generator set is counted as expected, not as a miss. That moves the question from the generator itself to the scope around it: the work that lands on neither the generator quote nor the labor built from it.
It is an assumption, not something Makeoff observed job by job. Makeoff reviews the takeoff, not the generator quote, and two contractors in this data did add a generator from a drawing review.
Set aside as expected · 27
Generator sets
Assumed quoted, with labor built off the quote
Counted as findings · 40
Installation and connection
Feeders, raceway, monitoring wiring, grounding, devices and labels
Gear and accessories
Switchboards, connection cabinets, disconnects, annunciators
Other
Startup and testing services, and findings with no mapped spec section
Setting aside 27 generator-set findings leaves 40, and half of those are installation and connection scope.
The split holds on working takeoffs: of the 14 findings left after generator sets, 7 were installation scope. Gear findings carry about $286K of estimated equipment, $165K of it two generator switchboards on drawing reviews. Installation findings carry about $77K across the 11 with an estimate.
Generator findings are rare: under 1% of the 11,130 missing-item findings Makeoff raised for customers in the window. For what estimators miss across all scope, see our Where Mistakes Hide report.
Twenty-one of the 27 generator-set findings came from drawing reviews, before any takeoff was loaded. The six raised on working takeoffs answer a narrower question: did the quote and its labor make it into the bid?
| Project type | Generator on the drawings | Takeoff at the time | Outcome |
|---|---|---|---|
| Public health laboratory | (4) 2,500 kW 13.8 kV natural gas, plus a 750 kW life-safety unit | 306 lines | Open (2 findings) |
| City operations and maintenance facility | 500 kW diesel | 689 lines | Ignored; feeders, annunciator and controls were carried |
| Multifamily | 500 kW | 449 lines | Open; still absent on a second upload |
| Warehouse | Emergency standby unit feeding a generator distribution board | 359 lines | Reviewed: "I want to know this" |
| Research laboratory | 30 kW / 37.5 kVA standby | 206 lines | Open |
The outcomes fit the workflow. At the operations facility, every connection to the generator was carried and the contractor ignored the finding. At the warehouse, the contractor still wanted the flag. On the multifamily job, the generator was still missing from a second upload. That one is worth a check before bid day.
Contractors carried 31 generator lines on customer takeoffs in Makeoff. Setting labor on those lines ran a median 35 hours per unit, from 4 to 95. Six carried no labor on the line, consistent with labor built separately. That separate build-up is where the checklist below applies.
Fourteen findings named equipment that sits between the generator quote and the gear quote: 11 pieces of generator gear and 3 vendor accessories.
Generator switchboards, connection cabinets and disconnects can come from either vendor, so each quote can assume the other has them. Whoever quotes them, the EC still mounts, feeds and terminates them.
County justice center · 395 lines
The takeoff carried a $440K generator and its pad, but not the 26 36 33 connection cabinet or the two 70A non-fused disconnects with interlock.
Federal research facility · 731 lines
Specs required one generator and one ATS remote annunciator. The contractor checked and marked it "this is a miss."
Two jobs · 7 and 287 lines
Both usually ship with the generator. The specs listed them separately, so confirm the quote matches the spec.
Two drawing reviews
Each one-line showed a 1,600A NEMA 3R generator switchboard, $165K of estimated equipment between them.
Twenty findings named labor and material that neither the generator quote nor labor built off it will carry.
They are small, about $77K across the 11 with an estimate. And they live in notes, schedules and details, not on the generator's equipment list.
Manufacturing plant · 46 lines
The page 3 diagram and the conduit schedule call for three 2-inch and two 1-inch Schedule 40 RNC runs to GEN-1 and its manual transfer switch. The takeoff's only conduit was 2-1/2-inch PVC. The generator there appears to be owner-furnished; the raceway to it is still EC work.
Industrial plant and maintenance facility · 829 and 6,874 lines
Generator specs required Form C contacts and BACnet points for control, operation and alarms. Feeders and annunciator controls were carried; the monitoring wiring was not.
Outpatient clinic · 114 lines
Notes required three modules: generator running, generator fault, and not in auto. Est. $2.2K.
1,250 kW generator · 287 lines
The grounding riser required a #3/0 copper grounding conductor, a system bonding jumper and rod electrodes at the generator. Est. $5.5K.
Office · 64 lines
The one-line required a sign at the service naming the generator's location and type. The NEC requires that sign for emergency, legally required and optional standby sources (700.7(A), 701.7(A) and 702.7(A)).
Drawing reviews show how much hides in a generator detail. On one multifamily project, a single detail produced five findings: a GFCI receptacle, a switch, cast boxes, a weatherproof plate, and the branch circuit back to the panel.
Not every finding held up. On a federal research facility, warning tape over a generator duct bank was already in the takeoff, and the contractor said so.
Startup, the NFPA 110 acceptance test and owner training usually come on the generator quote.
One finding fell here: an office project whose notes required NFPA 110 testing, ATS testing and retesting, reports and training. On a 48 kW unit priced as one line, startup is likely inside the generator price.
Startup
NFPA 110 acceptance test
Owner training
Electrician support during the load test, and outage coordination
A load bank, when the vendor quote excludes it
ATS testing, when the transfer switch comes from another supplier
Third-party NETA testing
Contractors recorded a decision on 9 of the 67 findings.
| Outcome | Findings | What they were |
|---|---|---|
| Completed | 4 | A 90 kW and an 80 kW genset, a generator load-center connection, generator grounding |
| Reviewed | 3 | A standby genset ("I want to know this"), a load-center feeder, duct-bank warning tape (already carried) |
| Ignored | 2 | Two gensets, one where every connection to it was already carried |
Both ignored findings were generator sets, which fits a quote-first workflow. Two contractors did add a generator from a drawing review, so not every shop works quote-first. For how one estimating group acted on Makeoff findings over eight weeks of live bids, read five scope misses caught on live competitive bids.
When the generator quote comes in and you build its labor, check each item against the quote and the takeoff. Every item except the last came up in this data set.
Want a second set of eyes on your next generator job?
Send us a bid you already priced, and Makeoff will flag the scope the takeoff doesn't carry.
In Makeoff's data, installation and connection scope. With quoted generator sets set aside, 20 of the remaining 40 findings were feeders and control raceway, monitoring wiring, grounding and bonding, and branch devices and labels at the generator.
It depends on the shop. Estimators we've talked to say some price the generator from a vendor quote and build installation labor off it, so a first pass with no generator line can be normal. Either way, the risk is the connection scope around the generator, which the quote doesn't include and labor built off the quote doesn't count.
The genset, enclosure and tank, and usually the battery, heater, controller, annunciator, startup and NFPA 110 test. Generator switchboards, connection cabinets and disconnects can come from the generator vendor or the gear vendor, so confirm which quote carries them. Whoever supplies them, the EC still mounts, feeds and terminates them.
The generator vendor usually carries startup, the NFPA 110 acceptance test and owner training. The EC usually carries electrician support and outage coordination during the load test, a load bank if the vendor excludes it, ATS testing when the transfer switch comes from another supplier, and any third-party NETA testing.
Section 26 32 13, Engine Generators, is the MasterFormat specification section for the generator set, in Division 26, Electrical. Much of the work that connects the generator to the building is not on the generator's equipment list. It sits in drawing notes, schedules and details.
This paper covers missing-item findings tied to Section 26 32 13, Engine Generators, and the work that connects a generator to the building.
Source: Makeoff production database, queried November 4, 2026.
Makeoff reviews electrical bids against the drawings and specs and flags scope the takeoff doesn't carry, like the generator connections in this paper. To see what it flags on one of your bids, visit makeoff.com.
Will Zacher is the CEO of Makeoff.