Job site is a duty-cycle problem
The specification that matters most here is not on the box. A home standby-adjacent portable runs perhaps thirty hours a year. A job site machine runs six hours a day, five days a week, and that is a completely different service life.
Three consequences follow.
Engine displacement matters more than the wattage. Two machines rated at 7,500 watts can have very different engines, and the larger one is loafing where the smaller is working. Loafing engines last.
Maintenance is on hours, not years. An oil change interval of 100 hours means monthly on a site and every three years at a house. The maintenance schedule is written for hours for exactly this reason, and a machine with an hour meter is worth more than one without.
Build quality shows up as downtime. A control panel that fills with water, a fuel tank that rusts, a frame that cracks — none of these matter at a house and all of them matter when the machine is loaded into a truck wet every evening.
GFCI is not optional
Temporary electrical power on a construction site is required to be ground-fault protected. In practice that means either GFCI receptacles on the generator itself or GFCI protection at the point of use, and an inspector will look.
Buying a machine with GFCI outlets built in is the simple route. If yours does not have them, the fix is inline GFCI adapters or a GFCI-protected temporary power box, and both are cheaper than a stop-work order.
Two practical notes. GFCI devices can nuisance-trip on long cord runs and on some inductive tools, which is a real annoyance and not a reason to bypass them. And a generator that is not bonded the way the GFCI expects can trip constantly — the grounding page covers bonded-neutral versus floating-neutral machines, which is the usual cause.
Sizing against real tool loads
| Tool | Running watts | Starting |
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| Circular saw, 7 1/4 in | 1,200-1,800 W | Brief inrush |
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| Table saw, 10 in | 1,800-2,000 W | Up to about 4,500 W |
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| Air compressor, 2 HP | 1,500-2,200 W | Much higher — starts against a load |
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| Miter saw | 1,500-1,800 W | Brief inrush |
|---|
| Concrete mixer | 800-1,500 W | Several times running |
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| Site lighting, LED | 100-400 W total | None |
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| Battery chargers, four of them | 200-400 W | None |
|---|
Ranges are typical for professional tools; the plate on your own tool is authoritative. The starting watts page explains why the second column decides the machine.
Add the running watts of everything that genuinely runs simultaneously, then add the single largest starting surge. A two-person crew with a table saw, a compressor and chargers lands around 4,500 running watts plus a 4,500W start — which points at the 7,500W class rather than the 5,000W one.
Cordless has changed the arithmetic
Worth saying because it genuinely reduces what many trades need. A crew running cordless saws, drivers and nailers needs a generator for chargers, lighting and the occasional corded tool — a few hundred watts plus one spike.
For that pattern a 3,500W inverter machine is enough, and it is quieter, lighter and cheaper to run than the open-frame machine the trade traditionally buys. Trades that still need real power are the ones with compressors, concrete equipment, welding, or heating.
A power station is also now a viable site product for chargers and lighting specifically — the job site scenario page works that through.
Theft, and the rest of site reality
- Generators are stolen constantly. Chain it, mark it, and photograph the serial number. An unattended machine overnight is an invitation.
- Cords are the other consumable. Run the right gauge for the length or you lose voltage and burn tools — the cord page covers sizing.
- Noise ordinances apply. Many municipalities restrict construction noise by hour, and an open-frame machine at 7am is the complaint that gets you a visit.
- Carbon monoxide indoors kills workers. Never inside a building under renovation, never in a basement, never in a partly enclosed space — the CO safety page applies with more force here than at a house, because the space is often unfinished and unventilated.
The short version
- Buy for duty cycle. Engine size and hour meter matter more than the wattage badge.
- GFCI outlets, or GFCI at the cord. It is a requirement, not a preference.
- Size for simultaneous tools plus one big start. Usually the 7,500W class for a crew.
- If the crew is cordless, buy smaller and quieter.
