Do You Need to Upgrade Your Electrical Panel? (Complete Santa Clara County Guide)

This article is general information for California homeowners. It is not legal, insurance, or code advice. Always confirm requirements with your local building department, utility, and a licensed electrician.

You likely need a panel upgrade if your home was built before 1990 with a 100-amp or 125-amp panel, you're adding an EV charger or other major appliances, the main breaker trips frequently, or you have a Federal Pacific, Zinsco, or certain Sylvania panel. Many older Bay Area homes can't safely handle modern electrical loads without upgrades.

In Santa Clara County, main panel upgrades typically cost $4,500–$16,000 depending on amp rating, service entrance work, and panel location. Upgrading from 100A to 200A service generally runs $4,500–$9,000 including permits and inspections. Subpanel replacements are usually less, around $1,800–$3,500.

If You Think You Might Need a Panel Upgrade, Do This First

Before you start calling around:

Check your main breaker rating. Open the panel door and look for the main breaker label: 60A, 100A, 125A, 200A, etc.

Look at the panel brand. Note if it says Federal Pacific, FPE, Stab-Lok, Zinsco, Magnetrip, Sylvania, GTE-Sylvania, or Challenger.

Write down your "pain points." Lights dimming when AC runs, main breaker tripping, can't run AC + microwave, planning an EV charger, adding a heat pump, etc.

Note your city and home age. For example: "1968 Cambrian home" or "1970s Sunnyvale Eichler" or "1980s Morgan Hill two-story."

Gather a few photos. Clear photos of the panel door (brand label) and inside with breakers visible.

Make one quick call to your city or an electrician. Ask: "For a panel upgrade in [your city], what permits and inspections are required, and what's the typical timeline?"

This gives any electrician in Santa Clara County enough information to give you a realistic plan instead of guesses.

Ever wonder why your lights dim every time the AC kicks on? Or why you can't run the microwave and toaster at the same time without the main breaker tripping?

Your electrical panel is probably maxed out.

Most homes in Campbell, Evergreen, Cambrian, and large parts of San Jose built before 1990 have 100-amp or 125-amp panels. That was fine when homes had one TV, no computers, no EV chargers, and air conditioning was optional.

Not anymore.

The average Bay Area home now pulls 80–120 amps during peak use. Add an EV charger (24–48 amps), heat pump HVAC (30–50 amps), or a few more high-draw appliances, and you're over capacity. Your panel can't safely deliver the power your home needs.

Here's how to know if you need an upgrade, and what that actually involves in Santa Clara County.

Signs You Need a Panel Upgrade

These are common indicators that your panel can't handle your home's electrical load anymore.

Frequent Main Breaker Trips

If your main breaker trips repeatedly, your entire electrical service is overloaded. This is different from individual circuit breakers tripping — those usually mean a specific circuit is overloaded and may just need load rebalancing or a dedicated circuit.

But when the main breaker trips, especially under normal household use, it means your total electrical demand exceeds what your service can safely deliver. That's a clear sign you need a panel and service upgrade.

In older homes, we often see 100A or 125A services that were adequate in 1970 but can't handle modern loads. The main breaker does its job and trips. But that isn't a fix — it's a warning sign.

Flickering or Dimming Lights

Lights shouldn't flicker when appliances turn on. If your lights dim when the AC starts, the dryer kicks on, or the refrigerator compressor runs, your panel or service may be undersized. The appliance draws a surge of current, voltage drops across the service, and lights dim.

This is especially common in Cambrian, Rose Garden, and Campbell homes from the 1950s–1970s that still have 100-amp service.

Buzzing, Crackling, or Burning Smell From the Panel

These are urgent. A buzzing sound can mean loose connections or arcing inside the panel. A burning smell often means overheated insulation or components. Both require immediate attention.

We see this most often in Federal Pacific, Zinsco, and older Sylvania panels, but it can happen in any overloaded or deteriorated panel.

You Can't Add New Circuits

If your panel is physically full — every breaker slot is occupied — you can't add new circuits for things like:

EV chargers
Outdoor kitchens
Hot tubs or spas
Workshops or home offices

Some electricians will suggest tandem breakers (two circuits on one breaker slot) as a workaround. That's code-compliant only in specific panels and situations, and it doesn't magically give you more total ampacity. The overall service can still be undersized.

You're Adding an EV Charger

A Level 2 EV charger pulls 24–48 amps continuously. That's like adding another large electric dryer or AC unit.

Most 100A and many 125A panels in older Santa Clara, Milpitas, and Morgan Hill homes can't support that load in addition to everything else.

We run load calculations before every EV charger install. If your existing load plus the charger exceeds 80% of your panel's capacity, a panel upgrade is usually required. We see this on roughly 60% of EV charger installs in older Santa Clara County homes.

You're Installing Solar or Battery Storage

Solar alone doesn't always require a panel upgrade, but batteries often do. If you're adding Tesla Powerwall, Enphase batteries, or other storage, you're connecting another significant load/source at the main panel.

Combined with solar inverter output and your home's existing load, you may exceed what the panel and bus are allowed to handle. California Title 24 also requires some reserve capacity for future loads. If you're already at 90% capacity, adding solar or batteries can push you over.

You Have a 100-Amp or Smaller Panel

If your main breaker is labeled 100A or less, you're on the low end for a modern Bay Area home. The minimum standard for new construction in California is 200A.

You'll find 60A and 100A panels in a lot of 1950s–1970s homes in parts of San Jose, Los Gatos, and older Gilroy neighborhoods. For modern loads, they're usually not enough.

Your Panel Is Federal Pacific, Zinsco, or Certain Sylvania Models

These panels should be replaced regardless of size. They have documented safety issues: breakers that don't trip properly, bus bars that corrode or fuse to breakers, and higher failure rates. Many insurance companies are now flagging and requiring replacement.

We cover this more deeply in our FPE/insurance article, but the short version: if you see "Federal Pacific," "FPE," "Stab-Lok," "Zinsco," or certain Sylvania markings, plan for replacement.

You're Buying or Selling a Home Built Before 1990

Home inspectors in Campbell, Sunnyvale, and Palo Alto routinely flag:

Undersized panels
Outdated brands (FPE/Zinsco/Sylvania)
Panels that don't meet today's clearance and labeling requirements

Buyers planning EVs or all-electric upgrades almost always ask about panel capacity. Replacing or upgrading the panel before listing removes a negotiation point and makes your home easier to sell.

What Size Panel Do You Actually Need?

Panel sizing depends on your home's total electrical load — what you're using now plus what you plan to add over the next 5–10 years.

100-Amp Panels

Common in Bay Area homes built before 1980. A 100A panel at 240 volts can deliver up to 24,000 watts (24 kW).

That's generally enough for:

Basic lighting and outlets
Gas furnace
Gas water heater
Gas dryer
A smaller AC unit or no AC

It is usually not enough for:

EV chargers
Heat pump HVAC
Heat pump water heater
All-electric kitchens and laundry

Who can keep a 100A panel:
Very small homes (under ~1,200 sq ft) with gas heat, gas water heating, no AC, no EV, and no plans to add big electrical loads. That's a small and shrinking slice of Santa Clara County.

Everyone else should plan on upgrading.

200-Amp Panels

This is the current standard for new residential service in California. A 200A panel at 240 volts can deliver up to 48,000 watts (48 kW).

A properly sized 200A service supports:

Heat pump HVAC
Heat pump or electric water heater
Electric dryer
Full electric kitchen
One typical Level 2 EV charger
Normal household loads

Who should upgrade to 200A:
Most Santa Clara County homes built before 1990 — especially in neighborhoods like Cambrian, Santa Clara, Sunnyvale, and Cupertino.

Typical cost to upgrade 100A to 200A (panel + service):
$5,500–$9,000 including permits and inspections.

225-Amp and 400-Amp Panels

These are for homes with very high electrical demand.

225A service:

Larger homes (3,000–4,000 sq ft)
Two EV chargers
Heat pump HVAC, heat pump water heater
Pool/spa equipment, workshops, or other high-draw loads

400A service:

Very large custom homes in Los Gatos, Monte Sereno, or hillside properties
Multiple EVs
Extensive workshop/garage equipment
Large battery systems and whole-home backup setups

Cost for 225A or 400A upgrades:
Typically $9,000–$16,000+ depending on service entrance work, panel locations, and utility requirements.

How Electricians Determine the Right Panel Size

We don't guess; we run a load calculation based on NEC Article 220. In plain English, that means:

Start with your home's square footage (general lighting and outlets).
Add required small appliance circuits (kitchen, laundry).
Add large fixed appliances (dryer, range, oven, water heater, HVAC).
Add continuous loads (EV charger, pool pump, dedicated equipment).
Apply demand factors — we assume not everything runs at once.

For EV chargers specifically, we look at:

Existing calculated load + proposed charger load

If that total exceeds 80% of your panel's rating, you're into upgrade territory.

Why Panel Upgrades Are So Common in Santa Clara County

Most panel upgrades we see fall into three big buckets.

1. Your Home Was Built for a Different Era

Homes in Rose Garden, Campbell, and older Sunnyvale or Santa Clara neighborhoods were wired in the 1950s–1970s for a completely different lifestyle.

Back then:

No EVs
Minimal AC
Fewer appliances
Far fewer electronics

Today the same house might have:

2–3 home offices
Multiple large TVs
Central AC or mini-splits
Electric or heat pump dryer
High-power kitchen appliances
Garage tools or hobby equipment

Even with more efficient LED lighting, the total household load is much higher. The panel and service simply weren't designed for that reality.

2. Electrification Is Pushing Loads Higher

California incentives and local policies are pushing homes toward:

Heat pump HVAC
Heat pump water heaters
Induction ranges
EV adoption

Each of those is a significant new electrical load. A gas furnace blower might use ~500 watts. A heat pump can pull 4,000–7,000 watts. A gas water heater barely sips power; a heat pump water heater can use around 4,500 watts. Add an EV charger at 5,760–11,520 watts, and your old 100A panel doesn't stand a chance.

3. Code Requirements Have Tightened

When you pull permits for:

EV chargers
Solar/battery systems
Major remodels or additions

City inspectors in San Jose, Palo Alto, Los Gatos, and other Santa Clara County jurisdictions will look at panel capacity. If your existing panel doesn't meet current standards, they can require an upgrade as a condition of approval.

How Much Does a Panel Upgrade Cost in Santa Clara County?

Here's how the pricing breaks down in practice.

Subpanel Replacements – $1,800–$3,500

Like-for-like subpanel replacement keeping existing circuits and location. Typically includes permit and inspection.

Common scenarios:

Garage subpanel replacement
Detached structure subpanel
Corroded or outdated subpanel feeding a specific area

This does not expand your main service capacity — it just replaces that subpanel.

Main Panel Upgrades – $4,500–$9,000

Main electrical panel upgrades (combination service entrance panels / meter-main combos) — overhead or like-for-like underground in the same location. Includes:

New combination service entrance panel
Service entrance conductors
Grounding and bonding updates
Whole-house surge protector (commonly included)
Panel labeling
City permits and inspections

Most common scenario for single-family homes in Campbell, San Jose, Santa Clara, Morgan Hill, and similar areas.

This tier generally does not include:

Rewiring old circuits inside the house
Fixing every junction box or receptacle issue
Underground trenching/digging

Complex Upgrades – $9,000–$16,000

More involved electrical service upgrades, including:

Panel relocations (moving panel to a new wall)
Overhead-to-underground conversions
Significant service entrance conduit/conductor work
225A or 400A service installations

This tier does not include:

Full house rewiring (quoted separately)
Underground trenching costs (see below)

What's NOT Included in Panel Pricing

Underground trenching/digging: Typically starts around $3,500 before driveway repair, landscape restoration, or concrete work.

Permit costs:

Most Santa Clara County cities: $650–$950
Palo Alto: often closer to ~$1,900
Campbell, San Jose, Los Gatos: typically $700–$900

Circuit wiring updates: Aluminum, cloth-insulated, or undersized wiring inside the home is a separate scope.

What Drives Price Variation

Panel location (garage/exterior vs inside a closet)
Overhead vs underground service
Amp upgrade (100A → 200A vs 125A → 400A)
Panel relocation distance and difficulty
PG&E coordination requirements
Access to attic/crawlspace
How much we need to bring up to current NEC and California code

An in-person assessment is the only honest way to get accurate pricing.

What to Expect During a Panel Upgrade

Here's what a typical 100A to 200A upgrade looks like in Santa Clara County.

Initial Assessment (1–2 hours)

We visit your home in, say, Almaden Valley, Sunnyvale, or Los Altos and:

Inspect your existing panel and service entrance
Verify panel brand and amp rating
Run a load calculation to determine correct panel size
Check accessibility and potential relocation issues
Identify grounding/bonding updates needed

You get a written quote with:

Recommended panel size
Itemized costs
Permit fees for your city
Estimated timeline
Notes on PG&E coordination

Permitting (1–6 weeks)

We submit plans to your city's building department:

San Jose, Campbell, Sunnyvale: often 3–10 business days
Cupertino, Los Gatos, Morgan Hill: often 7–14 business days
Palo Alto: commonly 10–20 business days

We handle the paperwork, plan submittals, and corrections.

PG&E Scheduling (2–12 weeks)

We coordinate with PG&E to schedule a service shutoff and reconnect. Typical lead times we see across Santa Clara County:

Summer (busy): 6–12 weeks
Winter (slower): 2–6 weeks
Emergencies (failed panel, safety hazard): sometimes 1–2 weeks with proper documentation

This is usually the longest part of the process and is outside any contractor's direct control — whether you're in Gilroy, Palo Alto, or anywhere else in the county.

PG&E Betterment Work

Here's something most homeowners don't expect: PG&E may require upgrades to their equipment as a condition of reconnecting your service.

What is betterment work?
If your existing service mast, weatherhead, conduit, or other utility-side equipment doesn't meet current PG&E standards, they can require you to upgrade it before they'll reconnect power. This is called "betterment work."

Common betterment requirements:

Replacing an old, corroded service mast
Upgrading weatherhead or riser conduit
Relocating the meter or service entrance to meet current clearances
Upgrading guy wires or support hardware

Who pays for it?
You do. Betterment work is the homeowner's responsibility, not PG&E's.

How much does it cost?
Typically $500–$2,500 depending on what needs upgrading. We handle this as part of the overall project, but it's a separate line item that doesn't show up until PG&E inspects your service.

When do you find out?
Usually during the PG&E scheduling process. Their inspector reviews your service entrance and flags any betterment requirements. We coordinate the work and get it approved before the final reconnect.

The bottom line: budget a little cushion for potential betterment work. It doesn't happen on every job, but it's common enough — especially in older Campbell, San Jose, and Sunnyvale neighborhoods — that you should plan for it.

Installation Day (6–8 hours)

Power will be off for about 6–8 hours.

Typical day in a Campbell, Saratoga, or Gilroy driveway:

PG&E disconnects service at the meter (often between 7–9 AM).
We remove the old panel and meter base.
Install the new combination service entrance panel.
Upgrade service entrance conductors as required.
Update grounding and bonding.
Install whole-house surge protection if it's in the scope.
Reconnect and clearly label circuits.
The city inspector does the day-of inspection while the panel is open.
PG&E returns to reconnect power, usually mid-afternoon.

You have power back by the end of the day.

Final Inspection (1–3 weeks later)

If stucco, siding, or drywall were cut, we coordinate repairs. Once that's complete:

The city schedules a final inspection.
The inspector verifies code compliance: conductor sizing, grounding, labeling, weatherproofing, etc.
Once approved, the permit is closed and you're done.

How to Prepare Your Home for a Panel Upgrade

You can make the day go much smoother:

Clear the area around the panel.
We need at least 3 feet of clear space in front and about 30 inches of width.

Plan for a full-day power outage.
No fridge, no internet, no AC/heat, no lights for 6–8 hours. Eat or move perishables, charge devices, and make arrangements if you work from home.

Secure pets.
Doors will be opening and closing all day. Keep dogs and cats safe and contained.

Tell neighbors if needed.
If your panel is close to a property line or shared access, a quick heads-up avoids surprises.

Open up attic or crawlspace access.
If those areas are blocked with storage, we may not be able to trace or adjust circuits if needed.

Keep the driveway clear.
We need space for the van, ladders, and material staging.

Do You Need a Permit for a Panel Upgrade?

Yes. Always.

Panel upgrades, service entrance work, and meter base replacements require permits in every Santa Clara County city.

Permits generally cover:

Panel replacement or service upgrade
Service entrance conductor upgrades
Grounding and bonding updates
Meter-main replacement
Load calculations and Title 24 compliance

Inspectors typically check:

Panel rating matches service size
Correct conductor size for the service
Proper grounding to water main and/or ground rods
Proper bonding of gas and water systems
Required AFCI/GFCI protection by area
Clear labeling and working clearances
Weatherproofing and sealing of exterior penetrations

Skipping the permit is a bad bet:

Can create insurance issues
Causes headaches when selling or refinancing
Can lead to expensive tear-outs and re-inspections later
Exposes you to fines or code enforcement problems

Permits exist so someone besides the contractor verifies the work is safe and code-compliant.

FAQs

How long does a panel upgrade take from start to finish?

Plan on 4–14 weeks total:

Permitting: 1–6 weeks
PG&E scheduling: 2–12 weeks
Installation: 1 day
Exterior repairs + final inspection: 1–3 weeks

The longer parts are permitting and PG&E scheduling.

Will I really need to upgrade if I add an EV charger?

Often, yes. We run a load calculation first. If your existing load plus the charger exceeds 80% of your panel's rating, code and safety both push you toward an upgrade. In older Santa Clara County homes, about 60% of EV installs require some level of panel or service upgrade.

Can I upgrade to 200A but keep my 100A main breaker?

No. The main breaker must match the service rating. If you're upgrading service to 200A, you'll have a 200A main breaker in a panel and meter-main combo that are rated for 200A.

Do I need to upgrade the wire from the pole to my house?

Usually PG&E owns and sizes the service drop (overhead wires from pole to mast). For typical 200A upgrades, they often don't need to change it. For 400A or unique situations, they may need to upgrade their equipment — that's handled on their side.

Can I reuse some of my old breakers in the new panel?

Sometimes, if you're staying within the same brand and the breakers are compatible and in good condition. In many cases, especially when switching brands or addressing known-problem equipment, a full set of new breakers is part of the upgrade.

Do I need a panel upgrade to add solar?

Sometimes. Solar connects to the main panel as a backfed breaker. If your panel and bus can handle the added solar current under the 120% rule, you may not need an upgrade. Many 200A panels can accommodate solar; most 100A panels can't without changes.

Which Santa Clara County cities have the longest permit times?

It varies, but we regularly see:

Palo Alto: 10–20 business days
Los Gatos, Cupertino: 7–14 business days
San Jose, Campbell, Sunnyvale: 3–10 business days

It depends on current workload at each building department.

What is PG&E betterment work and will I need it?

Betterment work is when PG&E requires you to upgrade utility-side equipment (service mast, weatherhead, conduit) before they'll reconnect service. It's common in older neighborhoods and typically costs $500–$2,500. We handle it as part of the project, but it's a separate cost that doesn't appear until PG&E inspects your service.

Why Homeowners in Santa Clara County Call Watson's for Panel Upgrades

Completed 200+ panel upgrades across Santa Clara County in the last few years, from Cambrian bungalows to Los Altos ranch homes and newer Morgan Hill builds.
Accurate load calculations so you get the right panel size, not a generic upsell.
We handle permits, PG&E coordination, and both inspections from start to finish.
Deep experience with 1950s–1980s Bay Area construction quirks: older service masts, tight closets, hillside homes, and Eichler panels in Sunnyvale and Palo Alto.
Clear, upfront pricing with itemized scopes, so you know what is and is not included.
We coordinate stucco/siding repairs when needed and schedule final inspections once everything is truly finished.
Licensed (C-10), insured, and familiar with Santa Clara County building departments and inspectors.
Gilroy-based and serving Campbell, Los Gatos, San Jose, Hollister, and throughout Santa Clara County.

Ready to Upgrade Your Panel?

Watson's offers a Complete Electrical Assessment & Panel Upgrade Quote for $179. We'll inspect your existing panel, run a load calculation, explain your options, and give you a clear quote with permit fees and an honest timeline.

Call or text Watson's Charging Stations & Electric at (408) 642-6547 to schedule your assessment. We serve Campbell, Los Gatos, San Jose, Hollister, and throughout Santa Clara County.

We'll tell you exactly what you need — and what you don't.