What Happens During a 100 Amp to 200 Amp Electrical Upgrade?
Planning a 100 amp to 200 amp upgrade for your Bothell home starts long before a new panel hangs on the wall. The work runs in a fixed order: an assessment measures what the house uses, a calculation sizes what it will use, the utility learns the plan, a permit documents it, and an inspector closes it out.
This walkthrough travels that route from first visit to final sign-off. Homeowners who want the capacity question answered first can read our 100 to 200 amp upgrade guide for Bothell homes, then return here for the process.
Initial Electrical Service Assessment
Every upgrade begins with eyes on the existing equipment. An electrician opens the panel, reads the main breaker, checks the bus bars that distribute power, and counts the spoken-for spaces. Conductor type, grounding, and the meter-to-panel route get noted too, because the new 200 amp gear must live in the same walls.
Plans count as much as present use: a heat pump, a second car, or a workshop changes the sizing conversation.
Residential Load Calculation
Next comes arithmetic. A residential load calculation tallies everything that draws power and weighs the total against the service rating, by a method the National Electrical Code prescribes. Results drive scope: some homes clear the bar with headroom, while others need the full service upgrade rather than a panel swap.
Curious what goes into that worksheet? Our electrical load calculation explainer lays out the categories.
Panel and Main Breaker Selection
With the load number in hand, equipment gets specific. Most projects land on a 200 amp panel with a matching main breaker, though some homes settle on 150 amps when the calculation supports it. Breaker spaces matter as much as rating: open slots today are cheaper than a second enclosure later.
Wondering whether the jump is necessary? Our comparison of 100 amp vs 200 amp service walks through that decision. Fit counts too: the enclosure must suit its wall and working clearances.
Meter and Service Entrance Evaluation
A panel is only half the path power travels. Utility electricity arrives through the service entrance: the meter base, the conductors to the panel, and the outside riser. Worn or undersized pieces get replaced as part of the job; a 200 amp panel fed through 100 amp-rated entrance equipment solves nothing.
Overhead and underground services differ; some homes need work reaching toward the utility's connection point. Our electrical service upgrade page covers that broader footprint.
Utility Coordination
Before wires move, the utility joins the project. Coordination covers scheduling a planned shutdown, the meter pull and reset, and who owns each piece of the path. Utilities handle the supply side; the electrician handles everything downstream.
Permit Application
Work of this scale is permitted. For Bothell addresses the electrical permit routes through Washington L&I, and the approved application authorizes both the installation and the inspection that follows. Scope notes from the load calculation feed the application.
Electrical Installation
Installation day turns the plan into hardware. Power comes down on schedule, the old panel and worn entrance components come out, and the new equipment goes in with fresh conductors, grounding updates, and breakers sized per circuit.
Labeling gets real attention. Every breaker earns a legible directory entry; an inspector reads the panel the way a future homeowner will, at a glance. Torque counts too: lugs tightened to specification run cool, loose ones run hot.
Re-energizing happens in stages. Circuits return one group at a time, each verified before the next goes live, so surprises stay easy to isolate.
Inspection and Final Testing
An inspector from Washington L&I checks the finished work against the approved permit: wiring methods, grounding, breaker sizing, and the directory. Approval closes the permit; a correction list names specific fixes. Voltage checks wrap up the job.
What Homeowners Should Expect
Most of the process is planning punctuated by a short stretch of hands-on work. Expect the power off during the core of installation day, and the inspection as the finish line. One page sums up the job:
- Initial assessment. Panel, service entrance, grounding, and future plans get reviewed.
- Load calculation. Every appliance load is tallied against the service rating.
- Equipment selection. Panel rating, main breaker, and breaker spaces get chosen.
- Service entrance evaluation. Meter base, conductors, and riser are checked for capacity.
- Utility coordination. Shutdown, meter work, and ownership boundaries are scheduled.
- Permit application. The documented scope goes to Washington L&I before work begins.
- Installation. The 200 amp panel and entrance updates go in; circuits are re-landed and labeled.
- Inspection and testing. Corrections happen if needed, then the system is tested under load.
Frequently Asked Questions
How long does a 100 amp to 200 amp upgrade take overall?
The hands-on installation is the shortest part of the calendar. Utility scheduling and inspection availability shape the timeline more than the wiring does, and those steps belong to others. Ask your contractor to sequence appointments so idle time lands where it does the least harm.
Can we stay in the house while the work happens?
Yes, and most households do. Plan around the hours without power: keep refrigerator doors closed, charge devices the night before, and arrange backup for medical equipment that depends on outlets. The panel area stays clear while the crew works, and everything returns to normal after the inspection.
Will a bigger panel raise my electric bill?
No. A panel distributes electricity; it does not consume more of it. Bills move only when usage does, which happens if new loads such as EV charging arrive alongside. Capacity and consumption are separate questions, and the load calculation keeps them that way.
Does every EV charger require a 200 amp service?
Not at all. Plenty of homes add Level 2 charging on a 100 or 150 amp service after a load calculation confirms headroom. The charger's dedicated circuit matters as much as the main rating, and load management can bridge tight situations. An assessment tells you which constraint is real.
A 100 amp to 200 amp upgrade rewards homeowners who treat it as a sequence rather than a single visit. For help mapping yours, dial (425) 285-8045 before any equipment is ordered.