Phase the cutovers by giving each floor or zone the same repeatable sequence: confirm the load, stage the temporary source with no outage, take a short approved outage window, switch over under a written rollback plan, verify, and hold before moving on. Repeating one routine on every floor keeps the crew practiced and keeps surprises small. Who approves each outage, how much notice is needed and how long the window can run depend on the contract and the building, so confirm them with the building engineer and your safety lead.
Electrical work on a construction site falls under OSHA’s wiring design and protection standard, 29 CFR 1926.404. It addresses grounding, ground-fault protection for 120-volt single-phase receptacle outlets on construction sites, and provisions for portable generators. Write the cutover plan against that standard and against anything the authority having jurisdiction adds. This article covers sequence and cutover mechanics, while the zone isolation guidance for occupied buildings covers how to keep work areas electrically separate.
Start with a phase map
Before any outage is requested, divide the building into phases by floor or by zone. Floor-by-floor phasing works when each floor has its own panel and riser connection. Zone-by-zone phasing fits floors where several panels serve different parts of the plate. Which approach applies depends on the existing distribution, so ask the building engineer for the one-line diagram and confirm which panels feed which spaces.
The table below lays out one sequence that repeats for every phase. Each row ends with a hold point, which is a sign-off the team collects before the next row begins. Treat it as a template to adapt, since your contract and building rules may add or remove steps.
| Phase | Goal | Power action | Hold point before moving on |
|---|---|---|---|
| 1. Survey | Know what the zone draws | Build a load list and review distribution drawings | Load list reviewed against the planned generator size |
| 2. Stage | Place the source with no outage | Set the generator, distribution and transfer equipment, then test | Dry run signed off by the electrical lead |
| 3. Cutover | Move the zone onto the temporary feed | Take the approved outage window, switch, verify | Zone confirmed stable, or rollback called |
| 4. Work | Renovate while the zone runs on temporary power | Monitor fuel, loads and connections | Work complete and inspected |
| 5. Return | Put the zone back on permanent power | Second outage window, restore, verify | Zone confirmed on permanent feed |
| 6. Re-feed | Prepare the next zone | Relocate or extend the temporary source | Next phase repeats from stage |
Approvals, notice, windows and rollback
Approval for a planned outage usually involves several parties, and the list depends on the building and your contract. Typical candidates are the building engineer, the property manager, the owner’s representative and your own safety lead. If the authority having jurisdiction has a say, get that in writing before the window is booked. Do not assume one sign-off covers every floor, because each cutover is its own event.
Notice and window length are set with the people who live in the building, and the tenant notice guidance covers how to word those messages. From the electrical side, agree the start time, the longest the outage may run and who has authority to extend it. Keep the window as short as the work allows, which is why staging and a dry run come first. Approval paths and tolerance for interruption differ by building type, as covered in office and clinical renovation power needs.
A rollback plan answers one question: what happens if the zone does not come up cleanly on the temporary feed. Name the trigger, name the person who calls it, and keep the permanent feed intact and re-energizable until the temporary feed has proven stable. Write down who is on site during the window, because a rollback needs the same people who made the switch.
Risers or per-floor units
There are two common ways to get temporary power to upper floors. One generator at grade can feed distribution up a riser, which keeps fuel handling and noise in one place. Separate units on each floor or zone shorten the cable runs and keep phases independent, but they bring fuel logistics, exhaust and placement questions into occupied space.
The better choice depends on riser capacity, what the building engineer will permit, and where equipment can be set safely. A hybrid is possible, with one source for a group of floors and a second for a separate zone. Start from a load list, using the generator sizing and load list guide, and then look at power distribution options and the transfer switch rental that will sit between the sources and the building.
Moving the source between phases
Moving the generator or extending distribution to the next zone is a second cutover, so give it the same hold points as the first. Either leave the generator in place and extend cabling, or relocate the unit and re-establish the feed from its new position. Each choice changes where fuel is delivered and who has to be on site.
Because Stag bills by single, double or triple shift, the phase schedule matters when you request a quote. Share how many hours per day each phase runs and whether work continues overnight so the shift pattern matches the plan. If a later phase changes the hours, tell the team early, since the right shift pattern depends on how the work is scheduled.
Shared systems
Elevators, life-safety systems, the fire alarm and emergency lighting need a decision before the first outage, not during it. Do not assume which circuits can be interrupted. Ask the building engineer which of these systems sit on the panels in each phase, and ask the authority having jurisdiction what notification or impairment steps apply. Those requirements depend on the jurisdiction and the building, so record the answers in the cutover plan instead of relying on memory.
Cutover checklist
The list below is a working checklist for the day of each cutover. It reflects the sequence above and should be edited with your electrical contractor and safety lead. Each item should have a named owner on the plan.
- Written approval for the outage window is on file and the notice has gone out.
- The load list for the zone matches the generator and distribution that were staged.
- The dry run is complete and the electrical lead has signed off.
- Fuel level is confirmed and a refueling plan is set for the work period.
- Shared systems on the affected panels have been confirmed with the building engineer and the authority having jurisdiction.
- The rollback trigger, the decision maker and the crew on site are written down.
- After switching, loads are verified and the team records the result before work begins.
Closing the loop with Stag
Stag Power Rentals supplies diesel generators from a yard in Dickinson, TX, with a fleet that runs from 20 kW to 2000 kW, so a multi-floor plan can start from one unit and be revisited as phases change. Send the phase map, the load list and the planned shift pattern, and the team can discuss what equipment fits each stage. For broader context on how Stag supports jobsites, see the construction industry overview, and when your sequence is ready, use the quote request form.
Frequently Asked Questions
Should each floor get its own generator or share one?
It depends on riser capacity, the building engineer’s guidance and the space available for equipment. One source feeding up a riser keeps fuel handling in one place, while per-floor units shorten feeds and keep phases independent. A load list for each floor is the starting point for comparing the two.
Who approves a planned power outage in an occupied building?
That depends on the contract and the building. The building engineer, property manager, owner’s representative and your safety lead are common participants, and the authority having jurisdiction may have its own requirements. Confirm the approval chain in writing before booking the window.
What should a rollback plan include?
It should name the trigger, the person who calls it and the crew on site. It should also keep the permanent feed intact until the temporary feed has proven stable. The plan should be reviewed with the building engineer before the window.
How do I handle the elevators and fire alarm during a cutover?
Confirm with the building engineer which of these systems sit on the panels in the phase. Ask the authority having jurisdiction about any notification or impairment steps. Both answers depend on the building and the jurisdiction, so put them in the cutover plan.
Does moving the generator between phases need a second outage?
It can, depending on how the temporary feed is arranged and how the zones are served. Treat the move as a cutover with its own approval, window and hold points. Confirm the details with your electrical contractor and the building engineer.