Is Your Electrical Panel Ready for an EV Charger?

The question people ask before buying an electric car is usually about range. The question that actually determines what the installation costs is about the panel in the garage.

It is a straightforward thing to check, and checking it before you order the car is a much better position than checking it afterwards.

Start with your service size

Open your panel door and look at the main breaker, normally at the top and larger than the rest. It will be stamped with a number: 100, 125, 150, or 200 are the common ones.

That number is how much power the house can draw at once. It is not the sum of the breakers below it — those routinely add up to far more than the service, on the assumption that you will never run everything simultaneously.

If you find screw-in fuses instead of breakers, your service is almost certainly 60 amps or less. That needs addressing before an EV charger is on the table, and honestly it needed addressing anyway.

What a Level 2 charger actually asks for

Most home Level 2 chargers go on a 40 or 50 amp, 240-volt circuit, and some support 60.

The detail that surprises people is continuous duty. Electrical code treats a load running for three hours or more differently from one that cycles, and requires the circuit to be sized at 125 percent of the continuous draw. So a 50 amp circuit delivers 40 amps of actual charging — the extra headroom is not waste, it is the margin the code requires for something that will run at full tilt all night.

Compare that to the rest of the house. An electric range is around 40 amps but runs in bursts. A dryer is 30 and runs for an hour. An EV charger is 40 continuous, most nights, for years. It is one of the largest sustained loads a home ever adds.

Whether your panel can take it

Three separate things have to be true, and they fail independently:

1. Enough service capacity. This is what a load calculation determines. It is not guesswork — it works through your heating and cooling equipment, water heater, range, dryer, and general lighting and receptacle load using a defined method, then compares the result against your service size. A 200 amp service usually has comfortable room. A 100 amp service with gas heat, gas water heating, and a gas range often does too. A 100 amp service already carrying a heat pump, an electric water heater, and an electric range frequently does not.

2. Physical space for the breaker. A panel can have plenty of capacity and no empty slots. This is a different problem with different and usually cheaper solutions.

3. A panel worth adding to. If your panel is a Federal Pacific Stab-Lok or a Zinsco, the honest answer is that it should be replaced regardless of the EV charger. Both have documented histories of breakers failing to trip under fault conditions, which is the one job a breaker exists to do.

When you do not need a full upgrade

A panel upgrade is not the only answer, and it is worth knowing the alternatives before accepting a quote that assumes it.

• A smart splitter lets two large loads share a single circuit by ensuring they never draw simultaneously — most commonly a dryer and a charger. Where breaker space is the constraint rather than total capacity, this genuinely solves it.
• Load management built into many modern chargers lets the unit monitor the whole-house draw and throttle its own charging to stay within the service. Since most cars sit on the charger for eight hours to take on a two-hour charge, throttling usually costs you nothing you would notice.
• Charging at a lower amperage. A 30 amp circuit still adds far more range overnight than any household outlet, and it may fit where 50 will not.

None of these help if the service itself is genuinely undersized. But we would rather tell you a splitter solves your problem than sell you a service upgrade you did not need.

Where this connects to heat pumps

If a heat pump is also on your list — and around here it often is — do the load calculation once, for both.

Panel capacity is the single most common thing that blocks either project, and discovering it twice is a waste. A house that needs a service upgrade for a heat pump almost certainly needs it for the charger too, and doing them as one planned project rather than two surprises is both cheaper and less disruptive.

The rebate angle

Both Tacoma Power and PSE currently pay toward home EV charger installation, and the terms are worth reading before you buy hardware.

Tacoma Power’s program is structured as bill credits and requires a licensed electrician for the 240-volt outlet portion, with proof of purchase due within 90 days. PSE runs its own rebate with its own requirements, including a substantially larger amount for income-qualified households that covers installation cost as well as the charger.

Peninsula Light — which serves Gig Harbor and the Key Peninsula — does not appear to have a current EV charger program. Be careful searching for one: results for “Peninsula Light EV rebate” often surface Peninsula Clean Energy, an unrelated California program.

You can see the current terms for all three on our rebates page.

The short version

Look at the main breaker. If it says 200, you are probably fine. If it says 100, it depends on what else is in the house, and a load calculation is a quick way to find out rather than guess. If it says 60, or you are looking at fuses, that is the conversation to have first.

If you would like someone to actually look at it, we install Level 2 chargers and we are a licensed Washington electrical contractor — so if the panel does need work, that is one company and one project rather than two.