How Long Does It Take to Install a Commercial Generator?
It’s a busy Thursday afternoon, and your team is working at full speed. Suddenly, the lights go out. Machines stop. Servers buzz. You can almost hear money slipping away. Gartner pegs the average cost of unplanned IT downtime at $5,600 per minute (Gartner, 2024). If you run a manufacturing plant, that number climbs even higher.
A standby generator can prevent these losses, yet many facility managers freeze because they’ve heard installation “takes forever.” It doesn’t, if you know what to expect.
At Camali Corp, we’ve installed more than 700 commercial generators across New Jersey, New York, and Pennsylvania. Here’s a clear breakdown of the six steps that get you powered up fast.
| Phase | Task | Typical Duration |
| 1 | Site assessment & load calculation | 1–2 weeks |
| 2 | Permitting & utility approval | 2–6 weeks |
| 3 | Concrete pad & fuel infrastructure | 3–5 days |
| 4 | Delivery & rigging | 1 day |
| 5 | Electrical & gas hook-up | 2–4 days |
| 6 | Commissioning, testing & training | 1–2 days |
Add it up and most projects land between five and ten weeks from signed proposal to go-live. Below we unpack each milestone, the wild cards that can drag things out, and how to keep your own timeline tight.
6 Key Phases in a Commercial Generator Installation Timeline
1. Site Assessment & Load Calculation (1–2 Weeks)
Every project starts with gathering the right data. Our engineers walk through your building, look at one-line electrical diagrams, and review your last 12 months of utility bills. We measure peak kVA (the highest amount of electricity your building uses) to make sure the generator is the right size, not too small and not too costly. Most delays happen when teams don’t have their energy statements ready, so it’s smart to gather drawings and bills in advance.
EEAT moment: “In our work with distribution centers, supplying utility bills on day one shaves a full week off the schedule,” says Camali operations manager Lisa Duarte, P.E.
2. Permitting & Utility Approval (2–6 Weeks)
Next, we send signed and sealed engineering plans to the Authority Having Jurisdiction (AHJ) and the local utility company for approval. This is required before connecting your generator to the grid. In smaller towns, permits may take just 10 days. In big cities like Newark or Queens, it can take up to 6 weeks—especially if you need permits for street work or emissions checks.
Tip: Schedule a pre-submittal meeting with the building inspector. A 30-minute call now avoids rework later.
Want to see how generators fit into larger designs? Learn more about Data Center Design.
You can also check FEMA’s emergency power best practices for compliance guidance.
3. Concrete Pad & Fuel Infrastructure (3–5 Days)
Once permits are approved, construction begins. We dig, frame, and pour an 18-inch-thick, rebar-reinforced concrete pad based on your generator’s size. If your system uses diesel fuel, we also install a UL-listed sub-base tank (a fuel tank that sits under the generator) or place steel posts (bollards) around an above-ground tank for safety.
The concrete needs to cure (harden) for about 48 hours before we can place the generator. Cold weather may delay curing by a day or two.
4. Delivery & Rigging (1 Day)
The generator is delivered from the manufacturer or a nearby distributor. A mobile rigging crew, trained workers who lift and install the generator using a crane, handles the setup. If needed, they block off traffic, attach a spreader bar (a tool that helps balance the unit), and safely lift the generator into place. Most installs take less than four hours. The only common delay is if the street-closure permit hasn’t been approved ahead of time.
5. Electrical & Gas Hook-Up (2–4 Days)
Our licensed electricians install conduits (protective pipes for wiring), pull feeder cables, and mount the automatic transfer switch (ATS)—the device that switches your power to the generator during an outage. For larger systems, we may install paralleling gear (equipment that connects multiple generators) or work with medium-voltage cables.
For natural gas generators, we need at least 2 psi of gas pressure. If your supply is lower, the gas company may need to upgrade your service while we work.
6. Commissioning, Testing & Training (1–2 Days)
Finally, factory-certified technicians run a two-hour load-bank test, which checks if the generator performs at full power. They also complete the NFPA 110 acceptance checklist, a national safety checklist for emergency power systems. Before we leave, we train your team on how to run weekly exercise procedures. Once the utility signs off, the system flips to “Auto,” so it’s ready when you need it.
Variables, Case Studies & Speed Hacks
What Slows a Project Down?
- Permitting Backlogs – Some municipalities meet only once a month. Start early.
- Custom-Order Generators – A non-stock, 600 kW diesel can take 10–14 weeks to leave the factory.
- Weather – Heavy rain washes out excavation; freezing temps delay concrete cures.
- Infrastructure Surprises – Buried utilities or asbestos panels add change orders.
- Late Design Changes – Moving the pad after drawings are stamped restarts the permit clock.
Real-World Timelines From Camali Corp
Case Study 1: Medical Office, Newark, NJ
Unit: 200 kW natural-gas
Timeline: 37 days
Why it moved fast
- Stock generator at distributor warehouse
- Pad reused existing footing
- City inspector pre-approved drawings
Case Study 2: Manufacturing Plant, Queens, NY
Unit: 400 kW diesel with paralleling gear (equipment that lets multiple generators work together)
Timeline: 68 days
What slowed it down
- Utility required updated short-circuit study
- Custom sound-attenuated enclosure (8-week lead)
- Two rainouts during slab pour
Five Ways to Shorten Your Generator Installation Timeline
| # | Action | Time Saved |
| 1 | Book a pre-planning call with the AHJ | 5–10 days |
| 2 | Choose an in-stock generator model | 4–8 weeks |
| 3 | Bundle pad, electrical, and fuel scopes under one contract | 3–5 days |
| 4 | Provide complete utility bills and drawings on day one | 1 week |
| 5 | Arrange a rental generator for critical operations during cut-over | Eliminates downtime risk |
ROI: Why Speed Pays
A mid-size manufacturer averaging $15,000 per hour in throughput can lose $360,000 in a single 24-hour outage. Compressing install time from ten weeks to six saves four weeks of exposure. Even if the odds of an outage are low, the risk-adjusted savings justify fast-tracking.
Frequently Asked Questions
Can installation happen without shutting down operations?
Yes. We schedule cut-overs during planned maintenance windows or overnight. A portable generator keeps mission-critical loads energized.
Does a larger generator always take longer to install?
Not automatically. Permit and utility review times drive the schedule more than kW size. A 500 kW in a small township can finish sooner than a 150 kW in midtown Manhattan.
How soon should we engage Camali Corp?
Ninety days ahead of your busy season provides cushion for permits and any OEM lead time.
Ready To Move Forward?
If power loss equals lost profit, waiting isn’t an option. Book a free site survey with Camali Corp today, and we’ll deliver a personalized timeline in 48 hours.
Request a Quote | Phone: (949) 580-0250
