Site services · Sourced through our provider network
Generators and fuel for a site that doesn't have power yet, or needs more than it has. We line up a local provider for the equipment and the refills, and we can help you plan around the utility's temporary service if that's the better route.
Two ways to get power
Plenty of jobs use both: a generator for the first weeks, then the utility's temporary service once it's inspected and connected. Here's how they compare.
| Utility temporary service | Generator | |
|---|---|---|
| How it works | An electrician sets a temporary meter base or pole, the local inspector signs off, then the utility sets the meter and connects. | A provider drops off a portable or towable unit, and cords or a distribution box run from it to the loads. |
| Lead time | Permit, inspection and the utility's schedule. One utility needs at least 10 business days when it has to build line.1 | As soon as a provider has a unit the right size. |
| What you handle | The electrician, the permit and the pole. In one city's rules the customer furnishes a wooden pole at least 20 feet long, set 4 feet in the ground.2 | A safe spot outdoors, fuel or a refill schedule, and GFCI protection on the outlets. |
| How long | Meant for temporary work. The same city limits temporary poles to service of an estimated year or less.2 | Days to months. The refills are what add up over a long job. |
| Good fit | Long builds with a steady load and a utility line nearby. | Short jobs, events, remote sites, and the weeks before the utility connects. |
Generator size calculator
Count what will run at the same time. This adds the running watts, then adds the one biggest starting surge, the way generator makers' own worksheets do it. The wattages are one maker's published figures. Your equipment's nameplate is better if you have it.3
How the sizing works
A coffee maker or a halogen light draws the same power from the first second. An air conditioner, a compressor or a saw pulls extra for a moment as its motor spins up. The worksheet method adds every running load, then the single largest extra starting load, because two motors rarely start in the same instant.3
| Load | Running watts | Extra watts to start |
|---|---|---|
| Window AC, 12,000 BTU | 3,250 | 3,950 |
| Coffee maker | 1,500 | 0 |
| Computer and monitor | 800 | 0 |
| Two halogen work lights | 2,000 | 0 |
| Circular saw, 7 1/4 in | 1,400 | 2,300 |
| Total | 8,950 | 3,950, the largest one |
8,950 running plus 3,950 for the air conditioner is 12,900 starting watts. If the saw and the air conditioner could kick on together, add both surges: 15,200. Wattages from one maker's published table.3
OSHA on temporary wiring
OSHA requires approved ground-fault circuit interrupters on every 120 volt, single-phase, 15 and 20 amp receptacle on a construction site that isn't part of the building's permanent wiring and that employees use. There's one exception: a two-wire, single-phase generator rated 5 kW or less, with its circuit conductors insulated from the frame and other grounded surfaces.4
Almost anything big enough for a site office is past that exception, so plan on GFCI at the generator or in the distribution box. A portable generator's frame can serve as the grounding electrode only when it feeds equipment on the generator or cord-and-plug loads through its own receptacles, with everything bonded to the frame.4
29 CFR 1926.405(a)(2).5
Where the generator goes
Carbon monoxide is the hazard people underestimate. OSHA's portable generator fact sheet is blunt about it, and about backfeeding.6
Keeping it running
A generator that runs out overnight takes the office heat, the pump and the lights with it. We arrange on-site diesel and gasoline deliveries for generators, light towers and equipment: 1,191 deliveries to 31 sites since August 2024. See fuel delivery for how that works.
Ask the generator provider for the tank size and the burn rate at your expected load, then set deliveries from that, not from a guess.
Powering a site office? The units we looked at have a 125 amp panel inside, and one has a 60 amp exterior disconnect. Have the electrician confirm what the office expects before you choose a generator. More on office trailer rental.
Send the address, the dates, what you need to run, and whether the utility is coming. Running and starting watts from the calculator help. We'll check which local providers have the right unit and can keep it fueled.
Questions
Add the running watts of everything that runs at the same time, then add the largest extra starting load among them. The generator's running rating has to cover the first total and its starting rating the second.
Running watts are what a load draws once it's going. Starting watts include the short extra pull a motor needs to spin up. A light or coffee maker has none; an air conditioner or saw can need more than double.
On construction sites, 120 volt, 15 and 20 amp receptacles not part of permanent wiring need GFCI under 29 CFR 1926.404(b)(1)(ii). Two-wire generators of 5 kW or less with insulated conductors are the exception.
It depends on the permit, the inspection and the utility. One large utility says line construction, when it's needed, takes at least 10 business days, and it won't set the meter until the inspector reports back.
Only through a transfer switch a qualified electrician installed. OSHA warns that a direct connection can backfeed and energize wiring for great distances.
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