How Do You Know When You Need an Electrical Panel Upgrade in Santa Clara County?

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 need an electrical panel upgrade when your main service is too small for your current and planned loads, not simply because one or two breakers trip. In Santa Clara County, panel upgrades are usually required when you have a 60A, 100A, or 125A panel and you're adding high‑draw loads like an EV charger, heat pump HVAC, or electric range, or when you have a known‑problem panel brand (Federal Pacific, Zinsco, certain Sylvania) that should be replaced. Frequent tripping of individual branch breakers usually indicates overloaded circuits or wiring issues, which are solved by circuit work, not a new panel. A licensed electrician should run a load calculation and inspect the panel to decide if an upgrade is truly necessary.

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

Before we talk upgrades, rule out the simpler stuff:

Note which breaker is tripping.
- Single branch breaker (labeled "Kitchen," "Bedrooms," etc.) → usually a circuit issue.
- Big main breaker at the top of the panel → that's a service/panel issue.
List your big loads: EV charger, AC / heat pump, electric range, electric dryer, spa, pool, heat pump water heater, workshop tools.
Check your main breaker size: 60A, 100A, 125A, 200A, etc.
Count open spaces in the panel. No open spaces means you can't add new circuits without creative (and sometimes code‑limited) solutions.
Look at the panel brand: Federal Pacific, FPE, Stab‑Lok, Zinsco, Magnetrip, certain Sylvania/Challenger models are replacement candidates on safety alone.

If it's always the same branch breaker tripping when you use too many things on that circuit, that's a circuit design/load issue. If you're trying to add big new loads and your main is small (100A/125A) or you literally have nowhere to put new breakers, now we're in panel‑upgrade territory.

You're standing at your panel in Willow Glen. The electrician just told you, "You probably need a panel upgrade" because you're adding an EV charger and thinking about a heat pump.

Meanwhile, that kitchen breaker has been tripping when you run the microwave and toaster together for years.

One of those problems is fixed by reworking circuits. The other is fixed by upgrading the panel. Getting them mixed up is how people spend $8,000 when they only needed $1,500 of circuit work.

Let's separate them.

What a Panel Upgrade Actually Solves (and What It Doesn't)

A panel upgrade does:

Increase how much total power your home can safely draw (100A → 200A, etc.)
Give you more physical breaker spaces for new circuits
Replace old, unsafe, or obsolete panel equipment
Make room for electrification (EVs, heat pumps, electric ranges, etc.)

A panel upgrade does not:

Fix a single overloaded 15A kitchen circuit
Stop a bad outlet or damaged cord from tripping a breaker
Repair loose connections or bad splices in random junction boxes
Magically prevent all breaker trips forever

Panel upgrades are about service capacity and equipment condition, not about avoiding doing the right circuit work.

When It's Probably a Circuit Problem, Not a Panel Problem

You likely do not need a panel upgrade yet if:

Only one or two branch breakers trip, and only when you use too many things on that circuit (microwave + toaster, space heater + hairdryer, etc.).
You have open spaces in the panel for new circuits.
Your main breaker is 200A and you're not trying to add huge new loads.
You haven't added any big electric appliances (EV, heat pump, big range) recently.

In those cases, the fix is usually:

Adding dedicated 20A circuits where needed (kitchen, bath, garage, office).
Cleaning up wiring and connections.
Rebalancing what's on which circuits.

That's where your "Why does my breaker keep tripping?" troubleshooting post kicks in, not a panel upgrade.

Real Signs You Might Need a Panel Upgrade

You're getting into true upgrade territory when:

1. Your Main Service Is Small (60A / 100A / 125A) and You're Electrifying

Common in older Campbell, Los Gatos, Santa Clara, and Gilroy homes:

You have a 60A, 100A, or 125A main breaker, and
You're adding one or more of:
- Level 2 EV charger (30–60A)
- Heat pump HVAC (30–50A)
- Electric or heat pump water heater (~4,500W)
- Electric range (40–50A)

The house was never designed for that stack of loads. A load calculation often shows you running too close to the limit, or over.

2. You Physically Have No Room for New Circuits

Your panel is either:

Completely full, and
Not approved for more tandems, and/or
Has old equipment that doesn't support modern AFCI/GFCI breakers you're required to use for new circuits.

If you want to add multiple new dedicated circuits (EV, kitchen, office, mini‑split, etc.) and there's literally nowhere to put them, a larger panel (and sometimes service upgrade) is the clean fix.

3. You Have a Known‑Problem Panel Brand

In Santa Clara County, we still see:

Federal Pacific / FPE / Stab‑Lok
Zinsco / Magnetrip / some GTE‑Sylvania / Challenger
Certain older Sylvania models

These have documented safety issues and are increasingly flagged by insurers. If you're going to invest in electrification, it's smarter to replace the panel now rather than add big loads to something that's already on borrowed time.

4. The Main Breaker is Tripping Under Normal Use

If the main (not just branch) breaker trips when the house is "normally" in use:

AC running
Range/oven on
Dryer going
Lights and outlets in normal use

…that's a service capacity red flag. Once we verify there isn't a specific wiring fault or obvious problem, we start looking at whether the main and panel are undersized for your actual household load.

What Size Panel Do You Really Need?

100A Panels

Common in pre‑1980 homes in San Jose, Campbell, Morgan Hill, and older Gilroy neighborhoods.

100A at 240V = 24,000W (24 kW)
Good for: gas heat, gas water heater, gas dryer, minimal AC, and no major electrification.
Struggles with: Level 2 EV, heat pump HVAC, heat pump water heater, full electric kitchen.

If you're trying to go "electric everything" on 100A, it's usually not enough.

200A Panels

Standard for most modern homes.

200A at 240V = 48,000W (48 kW)
Supports: one full‑size EV charger, heat pump HVAC, electric/HP water heater, electric dryer, electric range, and normal loads, when circuits are designed well.

Most Santa Clara County homes built before 1990 that are moving toward EV + heat pump + updated kitchen belong here.

225A / 400A Service

Used when:

Home is 3,000–4,000+ sq ft (think Los Gatos hillsides, larger Saratoga or Palo Alto properties).
There are multiple EVs, big shop loads, pool/spa combos, plus heat pump HVAC and an electric kitchen.

Not common for the average tract home in Campbell or Santa Clara, but we do see it in custom builds.

How Electricians Actually Decide if You Need an Upgrade

We don't eyeball it; we run a process.

Step 1: Fix or Rule Out Circuit Issues

Identify which branch breakers are tripping and why.
Move high‑draw appliances onto dedicated circuits where needed.
Inspect connections and repair any damaged or unsafe wiring.

If everything behaves after that, no panel upgrade needed.

Step 2: Load Calculation

We perform a load calc based on NEC–style rules, factoring:

Home square footage (general lighting/receptacles)
Small appliance circuits (kitchen, laundry)
Major fixed appliances (range, dryer, water heater, HVAC)
Continuous loads (EV chargers, pumps, etc.)
Planned additions (heat pump, second EV, etc.)

If the calculated load with planned upgrades sits under roughly 80% of your main rating, you're usually fine. Above that, we talk options.

Step 3: Panel Condition and Space

We look at:

Main breaker size and age of the gear
Brand/type (safe vs known‑problem)
Available spaces and tandem allowances
Whether your existing panel can support required AFCI/GFCI breakers

If the math says you're okay on capacity but the hardware is obsolete or unsafe, we may still recommend a replacement, but now you know why.

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

Typical ranges (not including full rewires or trenching):

100A / 125A → 200A Upgrade – $4,500–$9,000

Includes:

New 200A combination service entrance panel (meter‑main combo)
Service entrance conductor upgrades as needed
Grounding/bonding updates
Permits and inspections
PG&E disconnect/reconnect coordination

Does not include:

Rewiring old circuits inside the house
Fixing every outlet/switch issue (that's separate)

Key cost drivers:

Amp upgrade: $1,150–$1,725
Panel relocation: $920–$1,725 if it must move to meet code
Service entrance upgrades: $1,380–$2,875
Permit fees:
- Most Santa Clara County cities: $650–$950
- Palo Alto: around $1,900

Complex / Larger Service (225A / 400A) – $9,000–$16,000+

For bigger homes in Los Gatos, Saratoga, or custom builds that need more than 200A. Often involves:

Larger conduit and conductors
Bigger meter‑main equipment
Coordination with PG&E for service upgrade

What to Expect During a Panel Upgrade

High‑level, same as in the other posts:

Initial assessment (1–2 hours): inspect panel, run preliminary load calc, discuss future plans (EV, heat pump, remodel).
Permitting (1–6 weeks): submit plans to San Jose, Campbell, Sunnyvale, Los Gatos, etc.
PG&E scheduling (2–12 weeks): schedule meter disconnect/reconnect.
Installation day (6–8 hours without power):
- Power off in the morning
- Old panel removed, new panel/meter‑main installed
- Circuits reconnected and labeled
- Day‑of inspection while panel is open
- Power restored same day
Final inspection (1–3 weeks later): after stucco/siding/drywall repairs if needed.

FAQs: Panel Upgrade vs Circuit Fix

My kitchen breaker trips when I use the microwave and toaster – do I need a new panel?

Almost always no. That's a circuit design / load issue. The fix is usually adding or redistributing kitchen circuits, not upgrading the entire panel.

My main breaker has never tripped, but I want an EV and a heat pump. Do I need an upgrade?

Maybe. We run a load calculation. If your main is 100A or 125A and you're adding both, there's a good chance you'll need 200A. If you already have 200A, we may be able to keep it and just add circuits.

My main breaker tripped when we ran AC, dryer, and oven at once. Is that an automatic upgrade?

Not automatic, but it's a strong sign the service is near its limits. We'd:

Check for faults or obvious wiring issues
Run a load calc
If it shows the normal peak load is too close to your main rating, an upgrade is usually the safest fix.

Can I avoid upgrading by installing a smaller EV charger?

Sometimes. Dropping from a 48A charger to a 30A or 40A charger lowers the load. We'll run the numbers. Many 100A panels can support a lower‑amp charger if the rest of the house is mostly gas.

Will a panel upgrade stop all breaker trips forever?

No. Panels protect services, breakers protect circuits. A new 200A panel won't stop a 15A bedroom circuit from tripping if someone keeps running a space heater and hairdryer on that circuit.

Can I add a subpanel instead of upgrading the main panel?

Only if the main has enough capacity. A subpanel adds spaces, not amps. If the load calc says you're already maxed on 100A, adding a subpanel is just rearranging furniture on a ship that's already full.

How much does it cost to add a dedicated circuit vs upgrade a panel?

Adding a dedicated 20A circuit typically costs $600–$1,800 depending on wire run length, wall access, and whether permits are required. A full panel upgrade costs $4,500–$9,000. If you only need 1–2 new circuits and your panel has capacity and space, circuit work is much more cost‑effective than a full panel replacement.

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

We separate circuit problems from panel capacity problems so you don't buy a new panel when you only need new circuits.
We run real load calculations before recommending upgrades, especially in homes built before 1990 in Willow Glen, Campbell, Sunnyvale, and Santa Clara.
We're familiar with EV chargers, heat pumps, and electrification loads, not just "old school" panels.
We handle permits, PG&E coordination, and inspections across Santa Clara County so you're not caught in the middle.
Licensed (C‑10), insured, and current on California electrical code and Title 24.
Gilroy‑based and serving the entire county.

Not Sure If You Need a Panel Upgrade or Just Circuit Work?

If you're seeing breaker trips and planning new loads, but don't want to get sold a panel you don't need, Watson's offers a $179 Electrical Load & Panel Assessment. We'll:

Inspect your panel and major circuits
Run a load calculation with your planned upgrades (EV, heat pump, etc.)
Tell you plainly whether you need a panel upgrade, just circuit work, or both

Call or text Watson's Charging Stations & Electric at (408) 642‑6547 to schedule your assessment. We serve Santa Clara County.