Most San Jose homes run fine on a 200A service. A 400A upgrade comes up when the load outgrows a single 200A panel: a large or multi-unit home, an ADU sharing the same service, or a stack of high-draw additions like an EV charger, a heat pump, a battery, and a pool or shop pump all pulling at once. If your electrician has run the load calculation and 200A no longer covers it, 400A is the next standard step. Here is how the job works, what drives the price, and what to expect on timing in San Jose.

When a 400A service actually makes sense

A licensed electrician sizes your service from a load calculation, not a hunch. In practice you become a candidate for 400A when one of these is true:

  • You are adding an ADU or a second dwelling that will share the main service.
  • You already have, or plan to stack, several large loads together: a 48A or larger EV charger, a heat pump for HVAC, a heat-pump water heater, a battery system, and an electric range or shop equipment.
  • Your existing 200A panel is full, and a subpanel solves the space problem but not the total load.
  • A single large all-electric home runs past 200A on the calculation.

If your loads still fit inside 200A, a 200A panel upgrade or replacement is usually the better spend. We run the calculation first, so you are not paying for capacity you will never use. Our walk-through of a 100A to 200A upgrade covers where that line normally falls for an older San Jose home.

What a 400A upgrade includes

A 400A residential service in San Jose usually means a 400A meter-main feeding two 200A panels, or a single 400A-rated panel, plus a heavier service entrance and a grounding and bonding setup brought to current code. The scope typically covers:

  • Load calculation and the permit application with the City of San Jose.
  • The 400A meter-main and panel or panels, correctly rated conductors, and a code-compliant grounding electrode system.
  • Service mast or underground lateral work, depending on what the site has now.
  • PG&E coordination for the meter disconnect and reconnect.
  • Inspection and final sign-off.

What drives the cost in San Jose

There is no single sticker price for a 400A upgrade, and any contractor who quotes one over the phone is guessing. The number is built from the parts of the job that vary house to house:

  • Overhead versus underground service. An underground lateral with trenching costs more than a rebuilt overhead mast.
  • Panel location. The further the panel sits from the meter, the more conductor and labor the run takes.
  • Mast or lateral condition. A service mast or lateral that has to be rebuilt adds materials and time.
  • Panel relocation. Moving the panel to a new wall is a larger job than swapping it in place.

Because those swing so widely, a firm figure needs eyes on the meter, the panel location, and the service type. For a quote on your home, call 408-630-0548 or send the details through our quote form. We come out, run the load calculation, and put a written quote in front of you, permit included, before anything is ordered.

Timeline and permits

Plan the schedule around the permit and the PG&E coordination rather than the wiring. The physical work is often a day or so once materials are on site. What sets the calendar is the City of San Jose permit and the utility disconnect and reconnect window. We pull the permit, schedule the inspection, and line up the PG&E steps so the sequence does not stall halfway through.

Why homeowners call Monte for it

Monte Power & Electric is owner-operated by Abraham, a licensed C-10 contractor (CSLB #1156675) carrying $2M in general liability, with a live answer 24/7 across San Jose and the Bay Area. We size the service correctly the first time, handle the permit and PG&E coordination, and leave you inspected and signed off. Call 408-630-0548 for a 400A panel upgrade quote in San Jose.

Frequently asked questions

  • Do I need 400 amps, or is 200 amps enough?
    Most single-family San Jose homes run fine on 200A. You typically need 400A when a load calculation shows your combined demand exceeds what one 200A service can carry, for example an ADU on the same service plus several large loads like EV charging, a heat pump, a battery, and shop or pool equipment. A licensed electrician runs that calculation before recommending the size.
  • How much does a 400A panel upgrade cost in San Jose?
    The price moves with overhead versus underground service, how far the panel sits from the meter, whether the service mast or lateral has to be rebuilt, and any panel relocation. Because those variables swing widely from house to house, a firm number comes after a site visit. We give you the load calculation and a written quote, permit included, before any work starts.
  • How long does a 400A service upgrade take?
    The wiring itself is often about a day once materials are on hand. The overall schedule is set by the San Jose permit and the PG&E disconnect and reconnect window, which is why we start those steps early.
  • Does a 400A upgrade require a permit and PG&E involvement in San Jose?
    Yes. A service upgrade needs a City of San Jose electrical permit, an inspection, and coordination with PG&E for the meter disconnect and reconnect. We handle the permit, the inspection scheduling, and the utility coordination.
  • Can I add an EV charger and a battery after a 400A upgrade?
    Yes. Sizing to 400A is often done specifically to support an EV charger, a heat pump, and a battery on the same service. We plan the panel so those circuits are ready to add.

Outgrowing your 200A panel?

Send us the address and what you are adding, and we'll run the load calculation and tell you honestly whether you need 400A or a cleaner 200A setup. Get an estimate or call the dispatcher to talk it through.