Most O'Fallon homeowners don't think about their electrical panel until something goes wrong. But your panel has a finite capacity, and modern homes — with EV chargers, heat pumps, home offices, and more — can push 1990s and early-2000s panels past their limits. Knowing when an upgrade is warranted (and what it involves) helps you plan rather than react.

Signs Your Electrical Service May Need an Upgrade

Breakers that trip frequently. An occasional breaker trip is normal. Breakers that trip repeatedly on the same circuit — especially without an obvious overload cause — indicate the circuit is consistently at or near capacity. Multiple circuits doing this points to a panel that's undersized for your current load.

A 100-amp or smaller panel in a modern home. If you're in a home built before 1990 and you haven't had an electrical service upgrade, there's a reasonable chance you still have a 100-amp panel. Modern homes routinely need 150 or 200 amps. If you're adding an EV charger, upgrading HVAC, or adding a home addition, a 100-amp service almost certainly needs upgrading first.

Federal Pacific or Zinsco panels. These older panel brands have documented safety issues and were installed in homes built between the 1950s and 1980s. They are commonly found in O'Fallon homes built during that era. If you have one, having it evaluated by a licensed electrician is advisable regardless of whether you've experienced problems — some failure modes in these panels don't produce obvious warnings before they become hazards.

No room for additional breakers. If your panel is full and you need to add circuits, you have two options: a sub-panel or a full panel upgrade. Which makes more sense depends on your overall electrical load and future plans.

Lights that dim when appliances run. Dimming when a large appliance starts (refrigerator, AC, washer) indicates a voltage drop — the panel and service conductors are struggling with the sudden demand. It's worth having a licensed electrician evaluate whether the service capacity is the issue.

Planning a major addition or appliance upgrade. If you're adding a EV charger, an electric vehicle, a pool or hot tub, or a major HVAC upgrade, have your electrical panel evaluated before the work begins. Undersized service is a common reason electrical permits are held up.

What Does an Electrical Service Upgrade Involve?

An electrical service upgrade involves replacing the main panel (and sometimes the meter base and service entrance cable) with a higher-capacity unit. For most O'Fallon homes moving from 100 to 200 amps, the work includes:

• Coordinating with Ameren Missouri for a service interruption
• Replacing the meter base if needed
• Installing a new 200-amp panel with full capacity breakers
• Transferring existing circuits to the new panel
• Pulling the required permit and passing inspection

The work is typically done in a single day. Your home will be without power for a portion of that time while the panel is replaced — usually 4–6 hours. Plan accordingly for anything that requires power continuity (medical equipment, etc.).

What Does an Electrical Service Upgrade Cost in O'Fallon?

• 100-amp to 200-amp panel upgrade: $1,500–$3,500 depending on panel, meter base, and scope
• Panel replacement (same amperage, replacing defective unit): $1,200–$2,500
• Additional circuit installation at time of upgrade: $150–$400 per circuit

Our electrical team handles panel upgrades throughout O'Fallon and St. Charles County. Our technicians do not work on commission — you get a straight assessment of what your home actually needs, not a sales pitch for the most expensive option. Many home service companies operate differently; we don't.

FAQ

How long does a panel upgrade take?
Most panel upgrades are completed in a single day. Your home will be without power for a portion of that time — typically 4–6 hours while the panel is replaced and the utility reconnects service.

Will I be without power for the whole day?
No. The power interruption is typically 4–6 hours while the panel work is done and Ameren restores service. We coordinate the timing to minimize disruption.

Does a panel upgrade update my home's wiring?
No. A service upgrade replaces the panel and service entrance equipment — it doesn't update branch circuit wiring throughout the home. If your home has aging wiring issues (aluminum branch circuits, ungrounded outlets, knob-and-tube), those are separate items.

Should I notify my homeowner's insurance after a panel upgrade?
Yes. An electrical panel upgrade can affect your homeowner's insurance — some policies discount for upgraded panels, and some insurers want documentation of the work. Let your agent know after the work is done and inspected.

Can I add circuits at the same time as the panel upgrade?
Yes, and it's often the most cost-effective time to do it since the panel is already open and the electrician is already on-site. If you know you'll need circuits for an EV charger, hot tub, workshop, or other addition, plan those at the same time.

Call to Action

If your O'Fallon home's electrical panel is aging, undersized, or you're planning upgrades that will demand more capacity, AAA Home Services can evaluate your situation and give you straight answers on what's needed.

Request an electrical service evaluation today.