How Long a Panel Upgrade Takes
The electrical work itself takes 4 to 8 hours for a standard panel swap, or 1 to 2 days for a service upgrade with mast and meter work. Around that sit 1 to 3 weeks of permit processing and utility disconnect scheduling. Plan for the power to be off 4 to 8 hours on work day; the rest of the timeline is waiting, not working.
A panel upgrade is refreshingly quick as construction projects go: the crew is usually done in a day. The calendar time lives in permits and utility scheduling. This guide maps the full timeline and how to live through the power-off window.
Work-day timelines
Same-amp panel replacement: 4 to 8 hours, power off for 2 to 4 hours during the cutover. 100A to 200A service upgrade: 6 to 10 hours across one full day, power off 4 to 8 hours. 200A to 400A or difficult service work: 1 to 2 days, with the power off in windows each day. Subpanel addition: half a day. These are electrician-hours; the inspection happens the same day or the next business day, and the inspector's visit is brief if the work is clean.
The calendar around the work day
Quotes and load calculation: 1 to 2 weeks to get three electricians out. Permit: 1 to 3 weeks depending on jurisdiction; simple panel swaps are often over-the-counter, service upgrades get plan review. Utility scheduling: 1 to 3 weeks for the disconnect/reconnect appointment; the utility, not the electrician, sets this date, and it is the most common schedule driver. Inspection: usually within 1 to 2 business days of request. Total: 3 to 8 weeks from first call to done, with one day of actual disruption.
Planning the power outage
The power will be off for a contiguous block, typically 4 to 8 hours starting mid-morning. Before work day: charge phones and laptops; set the fridge and freezer coldest the night before and keep doors shut (food stays safe about 4 hours unopened); know that sump pumps, well pumps, medical devices, and security systems go dark, plan around each; reschedule if anyone in the home depends on powered medical equipment, or arrange backup power. Warn work-from-home household members; the wifi dies with the power. A good electrician confirms the outage window the day before.
What can delay the job
Discovering the meter socket or mast needs replacement once the old panel is off (common in older homes; adds hours and parts). Code-required grounding or bonding updates that were not visible at quoting. The utility missing its disconnect window, which reschedules everything. Failed inspection on grounding or labeling, usually fixed same-day. None of these are disasters, but each costs a day; keep the schedule loose the rest of the week.
After the upgrade
Label every breaker before the electrician leaves; unlabeled panels are a code issue and a future headache. Keep the permit card, inspection sign-off, and panel documentation with your house records; buyers' inspectors ask about panel age and permits. Update your homeowner's insurance if the old panel was a flagged brand; the replacement may change your policy terms. And enjoy the headroom: the next project (EV charger, heat pump) just got simpler.
The bottom line
One day of work, 4 to 8 hours without power, inside a 3 to 8 week project span dominated by permits and utility scheduling. Book the utility date early, plan the outage like a half-day event, and keep the week flexible for the surprises that old houses hide.
Figures current as of October 2026. Sources: HomeGuide and contractor-published 2026 cost guides; CPSC documentation on Federal Pacific panels.