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What Santa Rosa homeowners with 100-amp service should know before spending money on a panel upgrade
If you own an older home in Santa Rosa or Sonoma County and you’re thinking about installing an EV charger, one of the first questions you may hear is:
“Do I need to upgrade my electrical panel?”
The answer is: maybe — but not always.
Many homes in our area have 100-amp electrical service. Many also have underground PG&E service, which can make a full service upgrade much more complicated and expensive than homeowners expect.
Before you assume you need a new 200-amp panel, it is worth understanding your options.
At APG Electric, we believe electrical work is complicated — but the decision-making process should be simple. Our job is to help you understand what your home can safely support, what the code requires, and whether there is a smarter way to charge your EV without unnecessary cost.
Why EV chargers raise panel-capacity questions
A Level 2 EV charger is usually a 240-volt circuit. Depending on the charger and how it is configured, it may require a 30-amp, 40-amp, 50-amp, or larger circuit.
That does not automatically mean your home needs a 200-amp service upgrade.
What matters is the total electrical load of the home. An electrician should look at things like:
A homeowner may think, “I bought an EV, so I need the biggest charger possible.”
But in many cases, that is not true.
If your car sits in the garage overnight, even a lower-amperage Level 2 charger may provide plenty of range for daily driving.
The special problem with PG&E underground service
Many older homes in Santa Rosa and Sonoma County have underground PG&E service.
That can be good from an appearance and reliability standpoint, but it can make service upgrades more difficult.
If a home has 100-amp underground service and the homeowner wants to upgrade to 200 amps, the project may involve more than simply replacing the electrical panel. Depending on the property and PG&E requirements, a full service upgrade may involve:
This is why APG Electric does not automatically assume a service upgrade is the right answer.
Sometimes it is. Sometimes it is not.
The first step should be a thoughtful review of the home’s actual electrical capacity and the homeowner’s real charging needs.
Can you install a Tesla charger on a 100-amp panel?
Often, yes — but it depends on the home.
A Tesla Wall Connector, or another Level 2 EV charger, can often be configured to charge at less than its maximum output. Many homeowners do not need the maximum charging speed.
For example, a charger does not always need to be installed on a 60-amp circuit. In some homes, a smaller circuit may be a better fit.
The right question is not simply:
“Can I install a Tesla charger?”
The better question is:
“What is the safest and most cost-effective charging setup for this home?”
That may involve:
What is load management?
Load management is a way to add EV charging without overloading the home’s electrical service.
Instead of assuming all electrical loads will run at the same time, a load-management system can monitor the home’s electrical use and reduce or pause EV charging when other large loads are operating.
For some homes with 100-amp service, load management can make the difference between:
“You need a major service upgrade”
and
“You can safely charge your EV with the right equipment.”
That can be especially valuable when PG&E underground service makes a 200-amp upgrade expensive or disruptive.
Load management is not magic, and it is not right for every home. But it is often worth considering before spending thousands of dollars on a service upgrade.
When is a panel upgrade actually necessary?
A panel upgrade may still be the right answer in some situations.
Examples include:
In these cases, a panel or service upgrade may be a good long-term investment.
But it should be recommended because the home actually needs it — not because every EV charger installation is treated the same.
What about mobile homes?
Mobile homes require special attention.
Some mobile homes have limited electrical capacity, older equipment, or utility-service arrangements that make EV charging more complicated. In some cases, a full-size EV charger may not be realistic without upgrades. In other cases, a lower-amperage charger or carefully designed load-management solution may work.
The important point is that mobile homes should be evaluated carefully before any promises are made.
What if I have a Zinsco or other older electrical panel?
Many homes in Sonoma County still have older electrical panels, including Zinsco panels.
If you have an older panel, EV charging becomes part of a bigger safety and planning conversation. The issue may not be the EV charger alone. The issue may be the condition, reliability, and capacity of the electrical system as a whole.
APG Electric can help homeowners understand the options, which may include:
The goal is to make a good decision, not simply the most expensive one.
How much does EV charger installation cost?
The cost depends on the home.
Important factors include:
A simple installation may be relatively straightforward. A more complicated installation involving panel work, load management, trenching, or PG&E coordination will cost more.
That is why photos and a short review of the existing electrical equipment are so important before giving advice.
Do I need a permit for an EV charger?
In most cases, yes. EV charger installations are electrical work and may require a permit depending on the jurisdiction and scope of work.
Permit rules vary by city and county. APG Electric can help determine what is required for your project and whether permitting should be included.
Why APG Electric does not automatically recommend a 200-amp upgrade
Some contractors may look at a 100-amp home and immediately recommend a 200-amp service upgrade.
Sometimes that is the right answer.
But sometimes it is not.
For homeowners with underground PG&E service, a 200-amp upgrade can become a much larger project than expected. If a safe, code-compliant EV charging solution can be designed without that expense, it is worth exploring.
At APG Electric, we would rather help you understand your real options than push you into unnecessary work.
That may mean a panel upgrade.
It may mean a load-managed charger.
It may mean a smaller charging circuit.
It may mean waiting until other electrification plans are clearer.
The right answer depends on the home.
Questions APG Electric can help answer
If you are thinking about EV charging, we can help you answer questions like:
Start with a clear review, not a guess
EV charging does not have to mean a major electrical upgrade.
For many Santa Rosa and Sonoma County homeowners, the best first step is a practical review of the existing electrical system, the homeowner’s driving habits, and the real charging need.
If you are considering an EV charger and you have 100-amp service, underground PG&E service, an older panel, or concerns about upgrade cost, APG Electric can help you sort through the options.
Electrical work is complicated. We make it simple.
Call APG Electric to discuss your EV charger installation options.
