Do You Need a Panel Upgrade for an EV Charger?

Why does a 48-amp charger overwhelm a 100-amp panel?

A Level 2 charger is the largest single load most homes have ever added. At 48 amps it draws more than a central air conditioner, and it draws that much for hours at a stretch. Code treats it as a continuous load, so the circuit behind it needs 125 percent headroom: a 60-amp breaker and heavy wire for 48-amp charging.

Now put that next to a 100-amp main breaker. The charger alone claims 48 of those amps on paper, before the AC, the dryer, the oven, or a single light bulb. Tract homes built across the San Fernando Valley from the 1950s through the 1970s came with gas appliances and window units, and 100-amp service was generous at the time.

That is why a panel upgrade for EV charger circuits comes back yes so often for those homes and no for a house that already has 200-amp service. The panel is not broken. It simply has no room for a load this size. Current ranges for a 200-amp swap are on our panel upgrade page, and the honest first step is the math below.

How does the load calculation for a charger work in plain English?

NEC Article 220 is the part of the electrical code that decides how much power a house needs on paper. The method most electricians use for a single home takes four steps, and none of them need a meter reading.

• General loads: the code assigns 3 volt-amps to every square foot of living space, then adds a fixed allowance for the kitchen counter circuits and the laundry circuit.
• Fixed appliances: the nameplate rating of the range, oven, dryer, water heater, dishwasher, and disposal goes in at full value, and gas appliances go in at zero.
• Demand factor: the first 10,000 volt-amps count in full, and everything above that counts at 40 percent, since nobody runs every appliance at once.
• Air conditioning: the compressor goes in at 100 percent, since a hot Valley afternoon runs it for hours.

The charger comes last. We count it at its full rating, the conservative reading of the code, since it pulls full power for hours. Divide the finished total by 240 volts and you have the amps the house needs. A typical 1,600-square-foot Van Nuys home with central AC, a gas range, and a gas dryer lands somewhere around 65 to 75 amps before the car shows up.

Add a 48-amp charger and the paper number passes 110 amps, well over a 100-amp main. The same house with the charger set to 24 amps often stays under 100. That one line explains most of the decisions on this page.

Which Valley homes pass the math, and which fail it?

After enough load calculations you see the patterns before the tape measure comes out. Age, panel size, and fuel type tell most of the story.

A 1950s ranch house in Reseda or Van Nuys on its original 100-amp panel, with central AC added in the 1990s and an electric dryer, almost never carries a 48-amp charger. Swap the dryer and range for gas and the same house sometimes carries 24 or 32 amps.

A 1970s two-story in Northridge or Granada Hills with 125- or 150-amp service is the borderline case where the middle paths below earn their keep. A home in Encino or Sherman Oaks that got a 200-amp upgrade during a remodel usually passes with room for a second car later.

Two brand names change the conversation on the spot. If the 100-amp panel on the wall says Federal Pacific or Zinsco, the upgrade decision makes itself, since those breakers have a documented history of failing to trip, and many insurers will not write a policy on them.

What are the cheaper middle paths before a full upgrade?

A full upgrade is the right answer for many homes, but it is not the only answer, and we say so on the written estimate. Three middle paths handle the problem for a lot of Valley households.

The simplest is turning the charger down. A Tesla Wall Connector and most universal units adjust from 48 amps down to 24 or lower in the app or with a switch inside the unit, and the circuit matches that setting. At 32 amps a car still gains roughly 25 miles of range per hour, which refills a normal commute overnight.

Charger setting, circuit size, and the odds on a full 100-amp panel

The second path is a load-management device, which the code calls an energy management system. It watches the whole panel and throttles the charger the moment the AC and dryer come on, so the house never exceeds its rating. Some chargers build this in, and separate boxes do the same job for any brand. It has to be a listed device, wired exactly as its instructions say, and shown on the permit.

The third is a circuit-sharing switch that lets the charger borrow the dryer circuit while the dryer sits idle. It suits a garage laundry, where the two sit a few feet apart. Our EV charger installation page covers plug-in versus hardwired setups if the lower-amperage route appeals to you.

When is a subpanel the answer, and when is it not?

Homeowners ask about a subpanel more than anything else, usually because the main panel has no empty slots. A subpanel fixes that one problem well. It hangs in the garage, feeds from a single breaker in the main panel, and gives the charger and any future circuits short, clean runs.

What it cannot do is create capacity. A subpanel moves power around, so a house that fails the load math on 100 amps fails it with a subpanel too. The right order for that house is a 200-amp upgrade first, then a garage subpanel if the runs are long.

Where it shines is the 200-amp home with a panel full of tandem breakers. There the math passes, the slots are the only shortage, and a subpanel is the smaller job by a wide margin. We quote both on the same visit so the comparison is real.

Do LADWP rebates change the decision?

They can shift it, so check before you buy hardware. LADWP has offered rebates on Level 2 home charging equipment and runs time-of-use plans that make overnight charging cheaper. The programs change from year to year and funds run out, so the current terms on the LADWP site outrank anything printed here.

Two details matter for the panel question. Rebate programs generally ask for a permitted install and a listed charger, which rules out the unpermitted dryer-outlet shortcut. Some utility programs also favor networked chargers, the same ones that support load management, so the rebate and the middle path can line up.

If your address sits in Burbank, Glendale, or Pasadena, a different utility serves you, and each runs its own incentives. Rebates rarely cover a full service upgrade, so treat them as help with the charger, not the panel.

What permit does the work need, and who inspects it?

Every path on this page needs a permit, from a single new 240-volt circuit to a full panel swap. Inside the City of Los Angeles the permit goes through LADBS, while Burbank, Glendale, and Pasadena run their own building departments with their own counters. We pull it, meet the inspector, and hand you the signed record.

A panel upgrade adds one more moving part. LADWP has to drop power at the meter before the old panel comes out and restore it after, and that appointment has to line up with the permit and the work day. The inspector checks wire size, breaker size, grounding, and, on a load-managed install, the device listing.

Our Los Angeles electrician team does this work every week, and the permit line sits in every written estimate. Unpermitted charger circuits surface in buyer inspections and give an insurer a reason to argue after a garage fire, which is a poor trade.

How do you decide without overbuying?

Start with the label, the load math, and an honest look at how far you drive. A 30-mile commute needs about 10 kWh a night, which a 24-amp charger delivers in two hours. Nobody needs 48 amps for that. Long-distance drivers, two EVs, or a planned heat pump water heater push the answer the other way.

A+ Electric & Plumbing is a licensed electrician and plumber serving Los Angeles and the San Fernando Valley from Tujunga, and that pairing matters here more than it sounds. The heat pump water heater many EV owners add next is a plumbing and electrical job at once, so the load calculation we run for the charger can plan for it, and one crew handles both sides with no finger-pointing.

For Tesla owners weighing the Wall Connector against a 14-50 outlet, our Tesla charger installation page walks through the breaker math for each amperage. Whatever the car, a licensed electrician and plumber in Los Angeles should run the numbers before anyone buys a panel. A live person answers (818) 421-5290 around the clock, and written estimates are free.

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