Generator Wattage Chart for Job Sites: Tools by Watts
Determine power loads for saws, compressors, welders, and concrete mixers.
Powering the Job Site
Unlike home backup power, job site power demands are characterized by massive, rapid fluctuations. A contractor might run a heavy table saw for 30 seconds, shut it off, and then immediately turn on an air compressor.
Because construction tools use heavy-duty inductive electric motors, Starting Watts are the most critical factor when choosing a job site generator.
Power Tool Wattage Reference Chart
| Power Tool | Running Watts | Starting (Surge) Watts |
|---|---|---|
| Circular Saw (7-1/4") | 1,400 W | 2,300 W |
| Table Saw (10") | 1,800 W | 4,500 W |
| Air Compressor (1 HP) | 1,500 W | 4,500 W |
| Miter Saw (12") | 1,800 W | 3,200 W |
| Electric Drill (1/2") | 600 W | 900 W |
| Angle Grinder (4-1/2") | 800 W | 1,200 W |
| Concrete Mixer (1/2 HP) | 1,000 W | 3,000 W |
| Plasma Cutter | 4,000 W | 5,000 W |
How to Size a Job Site Generator
When multiple trades are working simultaneously, you must size the generator for the worst-case scenario: the two largest tools starting at the exact same time.
Example Scenario
Carpenter A is using a Table Saw (1800W Run / 4500W Start). Painter B is using an Air Compressor (1500W Run / 4500W Start).
- If they start them sequentially: The peak demand is 4500W (Table saw start) + 1500W (Compressor running) = 6000 Watts.
- If they pull the triggers at the exact same moment: The peak demand is 4500W + 4500W = 9000 Watts.
For this job site, a minimum 7,500W to 10,000W generator is required to prevent nuisance breaker tripping.
Conventional vs Inverter for Job Sites
For construction, Conventional Open-Frame Generators are heavily preferred. Why? Because job site tools don't care about "clean power" (THD). Conventional generators are cheaper, more durable, and have heavier alternators that can handle the massive physical torque shocks created by large saws cutting into knotty wood.