A commercial generator install looks like one job and prices like several. The unit, the transfer switch, a concrete pad, electrical work that touches the existing service, a fuel system, permits, sometimes a crane, and a commissioning day that has to prove the whole thing. Miss a line and the job pays for it.
Run the scope in job order. Load calculation first, because it sizes everything after it. Then the equipment, the mount, the electrical, the fuel, the permits, the rigging, and commissioning. At the end you should have a running set and an equipment record the PM program can attach to. How shops run that handoff in software is on generator service software. The recurring visits that follow are generator maintenance software.
Start with the load calculation
The generator, the ATS, the conductors, and the fuel supply are sized from the load. Quote a unit before the calc and you are guessing. A low guess fails on commissioning day. A high guess loses the bid.
Count three things: connected load, demand load, and the starting inrush of equipment with compressors or pumps. Inrush is the one estimators skip. A unit that covers the running load can still bog when a large motor starts against it.
Order
The unit and the ATS are two lines
Each has its own make, model, and rating. One combined number is harder for the customer to compare with another bid, and it hides which piece moved the price.
The generator
Spec kW rating, fuel type, enclosure (weather or sound attenuated), and cooling (air or liquid). Those choices drive price and site work, so they belong on the quote.
On larger sets, factory lead time can be the longest item in the schedule. Say it at the quote. How your shop marks up equipment, and which lead times you publish, are your numbers. This page does not invent them.
The automatic transfer switch
Settle location, sequence, service-entrance rating, and open versus closed transition before the line is priced. Each one changes scope. Deciding after the unit ships is how a change order starts.
Pad or structure
Ground-mounted commercial sets go on a concrete pad. Rooftop or structural steel is a different trade.
The pad
Excavation, forming, rebar, the pour, cure time, and conduit stub-ups set before the pour. Wrong stub-ups mean core-drilling cured concrete. Soft soil, slope, or a high water table changes the pad design and the cost. In seismic or high-wind places, anchoring follows the code and the AHJ, not a stock detail. Price the pad from the site you walked, not from a default.
Rooftop and steel
Vibration isolation, a structural review, and maybe another trade. It is not a swap for the pad line.
Electrical scope
- Conductors sized to the load and the run
- Conduit and trenching
- Overcurrent protection
- Disconnects
- Grounding and bonding
- The tie-in at the existing service
Long runs and voltage drop can push the wire size up, so the footage matters as much as the amps. Grounding and bonding follow the electrical code and the manufacturer, including the rules for a separately derived system where those rules apply. Do not replace that with a rule of thumb. Clearances to the building, openings, and property lines come from the installation manual and the local AHJ.
Where the system is emergency or standby power under NFPA 110, the standard's public scope is performance of the alternate source, the transfer equipment, the controls, and the accessory equipment out to the selected circuits. NFPA lists 2025 as the current edition. The edition on the job is the one the jurisdiction adopted. Source: NFPA 110. That citation does not set a clearance or a wire size.
Fuel system
Natural gas, LP, and diesel are three jobs. All three have to deliver what the unit needs at full load. Limits come from the AHJ, the utility, and the manual.
Natural gas
The line from the meter has to hold volume and pressure at full load. Confirm available pressure with the utility before you commit to a size. An undersized line is the classic miss: the set starts, then starves when the load stays on. Commissioning is where that shows up.
LP
Tank, regulator, vaporization for cold weather, the run to the set, and tank setting. An LP system that vaporizes in mild weather can fall short on a cold load. Clearances and placement are code and AHJ items.
Diesel
Tank sizing for runtime, spill containment, fill and vent, and the fire-code rules that follow tank size and location. Diesel also ages, so fuel maintenance belongs in the PM scope after the install, not as a one-time line you forget.
Spill containment and storage limits are local. If the engine is a stationary engine, operating limits and the records that go with them are a separate question. Read the EPA stationary engine pages and the site permit, and use the emissions recordkeeping guide for the shape of that file. This quoting page does not state an hour limit.
Permits and inspections
A job can pull electrical, mechanical, and building permits, and sometimes fire or environmental permits. Each one is a fee, a submission, and an inspection on the schedule. Put them on the quote. A permit you did not price is margin gone, plus a wait you did not plan. Which fees you pass through is your shop's rule. Do not borrow a fee schedule from another city.
Crane, rigging, and delivery
Past a certain size the set needs a crane, plus rigging, delivery, and a path to the pad. Walk the site before you quote the larger units. A set you cannot get a crane to is a set you cannot place on the day you promised.
Commissioning and handover
Manufacturer startup, initial readings, a transfer test, and a load test that asks the set to carry what you sized it for. An undersized fuel line or a grounding error can hide until that test. Train the customer and leave the startup readings with the equipment, not in a truck binder.
Generator acceptance testing is the proving step after the install. It is not the same document as the commissioning plan, and it is not the PM that follows.
The install becomes the service record
The finished job should leave make, model, serial, kW, fuel type, and the ATS on one equipment record. You cannot schedule maintenance on a unit you never wrote down.
Offering the first PM in the proposal is a sales choice. It does not, by itself, protect the warranty. Cummins says warranty work on its small-business standby line has to be done by an authorized dealer, and that a maintenance log supports warranty claims. Other manufacturers write different terms. Read the warranty you are about to hand the customer. Source: Cummins maintenance page.
Compliance with whatever standard governs the building is the same kind of claim: support it with the records the adopted edition and the AHJ ask for. Do not promise compliance in the quote.
What PowerOps keeps from the quote
The public quoting page groups lines under Equipment, Labor, Materials, Freight, Startup, Permits, and Subcontract, and the customer PDF keeps that grouping. The company catalog can hold make, model, and lead time. Cost stays off the customer PDF. An accepted quote can become a draft work order or a draft invoice. Someone still reviews that draft before it is scheduled or sent.
Customer, site, and equipment are entered once and carry from the quote to the job. Access notes from the site walk should be the notes the crew sees, not a second typing. Audited completion of the startup keeps the account, the server time, the attestation, and a snapshot. That snapshot is the sign-off. It does not prove the test happened the way the narrative says. Working records can still be corrected through the paths the product allows.
Matching equipment can feed the PM schedule after the install. The unit you set is the unit you maintain, if the serial on the quote and the serial on the schedule are the same one. Book a demo to run one install quote through to a draft work order. PowerOps does not publish a price on this page.
Before you send the number