You need a 200 amp panel upgrade if your breakers trip when the dryer and microwave run together, if your panel is a 100 amp unit from before 1980, or if you're adding an EV charger, heat pump, or ADU. Any one of those is enough reason to have an electrician look at your service. Two or more, and you're almost certainly overdue.
Below we walk through the specific signs we look for on service calls across San Mateo, what changes between a 100 amp and a 200 amp panel, what a 200 amp panel upgrade costs here in 2026, and when it's time to stop resetting breakers and call someone.
What a 200 amp panel actually means for your house
A 200 amp panel upgrade is an electrical service change that raises your home's total power capacity from 100 or 125 amps to 200 amps, which is enough to run modern appliances, an EV charger, and a heat pump at the same time without tripping the main breaker.
Amps measure how much electricity can flow into your house at once. A 100 amp service was generous when homes had a fridge, a stove, and a few lights. A 200 amp service is the current baseline for a single-family home in San Mateo County - it's what PG&E expects to see when you add a large load, and it's what most cities here require before they'll sign off on an ADU or a full kitchen remodel.
If you're weighing whether to repair what you have or replace it, the honest answer usually comes down to age. A 40-year-old 100 amp panel that's still working fine is a candidate for electrical panel repair San Mateo CA if the only issue is a worn breaker. A 40-year-old panel that's already tripping under normal load is a candidate for replacement, because you're going to end up there anyway.
The clearest signs you need a 200 amp panel upgrade in San Mateo
San Mateo has a specific housing mix - a lot of 1920s-to-1960s bungalows in the Aragon and Hayward Park areas, mid-century tract homes in Beresford and Parkside, and newer infill near Bay Meadows - and the electrical symptoms we see track closely with when each neighborhood was built.
Here's what we actually find on the calls that turn into a 200 amp panel upgrade San Mateo homeowners didn't plan for:
- The main breaker trips, not a branch breaker. If you're resetting the 100 amp main on the panel itself, you're over capacity. Branch breakers tripping one at a time is a smaller problem.
- The panel cover is warm to the touch. Warmth at the dead front means resistance somewhere in the bus or the main lugs. That's a fire-risk symptom, not a nuisance.
- You have a 60 amp or 100 amp service. Look at the main breaker handle - it's stamped. If it says 60 or 100, you're running a service sized for a house half the size of yours.
- You have a fuse box, not a breaker panel. Screw-in fuses and cartridge fuses mean the service hasn't been touched in decades. A fuse box replacement San Mateo CA is the modern equivalent of the same job.
- You're out of breaker slots. If every slot is full and someone has doubled up circuits to make room, you've hit the ceiling of what that panel can do.
- You're planning a big load. EV charger, heat pump water heater, induction range, mini-split, hot tub, ADU - each of those is a 30 to 60 amp addition, and a 100 amp service can't absorb it.
- Your lights dim when the AC kicks on. That flicker is voltage drop, and it usually points to an undersized service or a loose neutral.
Two or more of those together is our trigger to recommend the upgrade rather than patch it.
100 amp vs 200 amp panel in San Mateo CA: what changes in practice
The 100 amp vs 200 amp panel San Mateo CA comparison isn't about a bigger box on the wall - it's about how many things you can run at once and what you're allowed to add later.
On a 100 amp service, you're typically looking at a practical ceiling of about 24,000 watts of connected load. That covers a gas furnace, a gas water heater, a gas range, and a few kitchen circuits. Add an electric dryer, a central AC, and an EV charger, and you're past the limit before you've turned anything on.
On a 200 amp service, you have roughly 48,000 watts of headroom. That's enough for a fully electric kitchen, a heat pump HVAC system, a heat pump water heater, a Level 2 EV charger, and a 60 amp subpanel out to a garage or ADU - all running at the same time.
The physical work is more than swapping a box. A 200 amp service usually means a new meter main, a new service mast or riser, larger service entrance conductors, a new grounding electrode system, and often a new weatherhead and PG&E coordination for the drop. Most San Mateo homes built before 1970 also need the panel moved or the meter relocated to meet current clearances - 36 inches of working space in front, 30 inches wide, 6 feet 6 inches of headroom.
If you're adding a detached garage, an ADU, or a workshop, the right answer is often a 200 amp main service with a subpanel installation San Mateo CA feeding the outbuilding. That keeps the big loads off the house panel and gives you a clean place to add circuits later.
Do I need a 200 amp panel for an EV charger in San Mateo?
Not always, but often - and the math is unforgiving. A Level 2 EV charger draws 32 to 48 amps continuously, which is 40 to 60 amps of breaker capacity. On a 100 amp service, that's more than half your total capacity going to one circuit.
There's a workaround. A load management device or a smart splitter can let you install a 40 amp charger on a 100 amp service by automatically pausing it when the dryer or range is running. We install those when the panel genuinely doesn't need replacing. But if you're also planning a heat pump, an induction range, or a second EV, the load management approach just delays the inevitable.
For a 200 amp panel upgrade for EV charger San Mateo CA projects, we usually quote the panel and the charger circuit together. Running the 6-gauge or 4-gauge wire, installing a NEMA 14-50 or hardwired EVSE, and pulling the permit is a half-day of work once the panel is in. Doing it as a separate job later costs more because the wall has to come open twice.
If you're in an older neighborhood like Hayward Park or Sunnybrae and your service drop comes off a shared pole, PG&E may also need to upgrade the transformer or the drop. That adds two to six weeks to the schedule, so it's worth knowing early.
How much does a 200 amp panel upgrade cost in San Mateo CA?
Typical 2026 pricing for a 200 amp panel upgrade in San Mateo runs $2,800 to $6,500 for a straightforward overhead service, and $4,500 to $9,000 when the meter has to be relocated, the service is underground, or the mast and riser need replacing.
Here's what drives the spread:
- Panel and meter main: $600 to $1,400 in parts for a quality 200 amp panel with a main breaker and copper bus.
- Permit and inspection: $250 to $600 depending on the city. San Mateo, Burlingame, and Belmont each have their own fee schedules.
- Labor: one to two days for a standard swap, three to five days if the service entrance, mast, or grounding system has to be rebuilt.
- PG&E coordination: no direct charge, but the disconnect and reconnect window can add a day or two to the schedule.
- Extras: whole-home surge protection ($300 to $600), a generator interlock kit ($400 to $900), or a dedicated EV circuit ($700 to $1,400).
Underground service is the big variable. A lot of San Mateo homes west of El Camino have overhead drops; a lot east of it are underground. Underground means trenching, conduit, and sometimes a new pull section at the property line, which is why those jobs land at the top of the range.
We quote the whole job upfront - panel, permit, PG&E coordination, inspection - so there's no surprise line item when the inspector shows up.
Common mistakes we see homeowners make
The most expensive mistake is waiting. A panel that's warm, buzzing, or tripping the main isn't going to fix itself, and the failure mode is a fire, not a blown fuse.
Other things we see:
- Adding a big load without checking capacity. Installing a 50 amp EV charger on a 100 amp panel without a load calculation is how you end up with a main that trips every time the oven preheats.
- Hiring the cheapest bid. A 200 amp upgrade involves a permit, an inspection, and a PG&E disconnect. If the quote doesn't mention any of those, the contractor is planning to skip them.
- Replacing the panel but not the service entrance. A new 200 amp panel fed by 100 amp conductors is a code violation and a hazard. The wire has to match the panel.
- Ignoring the grounding electrode. Older San Mateo homes often have a single ground rod or a water-pipe ground. Current code wants two rods or a Ufer ground, bonded properly. It's a small line item and a big safety item.
- Assuming a subpanel solves everything. A subpanel doesn't create capacity. If the main service is 100 amps, a subpanel just moves the overload downstream.
If you're not sure which side of the line you're on, a load calculation takes about 30 minutes and tells you exactly how much headroom you have. That's the number that decides whether you need a 200 amp panel upgrade San Mateo or just a few new circuits.
When to call a professional
Call an electrician the moment you see any of these: a warm or discolored panel cover, a burning smell near the panel, scorch marks on a breaker, a main breaker that trips more than once a month, or a service that's still fuse-based. Those aren't DIY items.
We handle 200 amp upgrades across San Mateo and the surrounding Peninsula - San Mateo proper, plus Electrical Panel Upgrade in Burlingame, Electrical Panel Upgrade in Belmont, and Electrical Panel Upgrade in San Carlos. Same-day service is available for panels that have already failed, and we run 24/7 emergency calls for no-power and burning-smell situations.
If you want a straight answer on whether your service can handle what you're planning, we'll come out, pull the cover, run the load calc, and tell you what we'd do in your house. No pressure to upgrade if you don't need it.
Frequently Asked Questions
How do I know if I need a 200 amp panel in San Mateo CA?
Check the number stamped on your main breaker. If it says 60 or 100, and you're adding an EV charger, heat pump, or ADU, you need 200 amps. If the main breaker trips under normal load or the panel cover is warm, that's an immediate call.
What are signs a home needs a 200 amp upgrade in San Mateo California?
Frequent main breaker trips, a warm panel cover, a fuse box instead of breakers, no open breaker slots, dimming lights when large appliances start, and any plan to add a 30 amp or larger load. Two or more of those together means the service is undersized.
How much does a 200 amp panel upgrade cost in San Mateo CA?
In 2026, expect $2,800 to $6,500 for a standard overhead service and $4,500 to $9,000 if the meter has to move or the service is underground. Permit, PG&E coordination, and inspection are included in our quotes.
Who installs 200 amp panels near me in San Mateo?
San Mateo Panel Pros installs 200 amp panels throughout San Mateo and the Peninsula. We pull the permit, coordinate the PG&E disconnect, and handle the inspection. Call +1 650-372-5030 to schedule a load calculation.
Do I need a 200 amp panel for a heat pump or induction range?
Usually yes if you're also keeping a gas dryer, AC, or EV charger. A single heat pump might fit on 100 amps with load management. A heat pump plus induction range plus EV charger will not - that combination needs 200 amps.
Get help with Electrical Panel Upgrade in San Mateo
If any of the signs above sound like your house, we'll come out and give you a straight answer. Our team handles Electrical Panel Upgrade San Mateo CA projects every week - from a simple 100-to-200 swap to a full service rebuild with a new mast, meter main, and grounding system.
Call +1 650-372-5030 to schedule your load calculation and upfront quote.