Start with an assessment of equipment condition, available circuit spaces, and the home’s calculated electrical demand.
What the panel actually does
Your panel distributes electricity to separate circuits for lighting, outlets and equipment. Breakers protect circuit wiring from excessive current. The panel’s rating, the service capacity and the space available for breakers are different things.
An empty breaker position does not prove that your home can support a new large load. A full panel does not prove that the electrical service is too small. A qualified electrician must assess both.
Replacement, more circuit space, or a service upgrade?
Replacement may address damaged equipment, corrosion, unavailable compatible parts or a condition identified during inspection. A subpanel may add circuit spaces but does not create additional service capacity. Increasing the service involves equipment beyond the panel and may require utility work.
Ask the electrician to identify the actual constraint in writing. If a particular brand or model is said to be unsafe, request the model identification and a specific recall, manufacturer notice or documented condition. Age or a brand name alone is not a complete diagnosis.
100 amps or 200 amps? Start with demand.
The right capacity depends on the loads the home needs to support. EV charging, an electric range, a heat pump or a renovation may change that calculation. A 200-amp upgrade is not automatically necessary for every project.
A load calculation applies the relevant code method to existing and proposed equipment. It is not the sum of the numbers printed on every breaker. Ask whether a lower charging rate or an approved load-management system could meet your needs before choosing a larger service.
What the project should include
- An assessment and proposed equipment schedule, with panel and breaker models.
- A clear distinction between panel work, meter equipment and a service-capacity change.
- Permit responsibility, required inspections and any utility disconnection or reconnection.
- An outage plan, including arrangements for medical equipment, refrigeration and working from home.
- Circuit identification, labeling, cleanup and any wall restoration.
Naperville coordination
Use the local permit guide before scheduling installation. For a change in service capacity or service equipment, have the contractor establish the utility’s scope and timing before promising an installation date.
The City publishes a residential load worksheet. Ask which calculation and supporting documents your project needs. City residential load calculation worksheet ↗
What changes the quote
A panel replacement in the same location can have a different scope from a service upgrade with exterior equipment, new service conductors, relocation or building repairs. Compare surge protection, circuit protection, grounding and bonding work, permit fees and utility charges as separate inclusions.
Ask: What evidence supports this scope? What remains unchanged? What would trigger additional work? Who signs off on completion? Keep answers alongside the quote comparison worksheet.