200-Amp Underground Electrical Service Upgrade

Project Overview

The homeowners contacted Pro Build Solutions because their existing 100-amp electrical service had reached its practical capacity. The existing 20-space panel had no remaining room for the additional electrical loads they were considering, including future kitchen improvements, a hot tub, sauna, EV charging, and garage upgrades.

The existing electrical service was already underground and ran approximately 80 feet from a ComEd pedestal to the rear of the house. The service equipment was reported to be original to the older home and included an Arrow Hart Murray panel that was full, showed corrosion, and lacked the grounding and exterior disconnect configuration planned for the upgraded system.

Pro Build Solutions performed a residential load calculation and developed a 200-amp service upgrade designed to provide substantially more panel capacity while retaining the property's underground service arrangement.

The project included electrical design, load calculation, permit documentation, utility coordination, excavation, underground conduit and conductors, new service equipment, a new 200-amp Siemens panel, grounding and bonding improvements, inspections, concrete restoration, grading, and reseeding.

Project Goals

• Increase the home's electrical service capacity from 100 amps to 200 amps.
• Replace the existing full 20-space panel with a larger service panel offering additional circuit capacity.
• Provide capacity for future electrical loads including a hot tub, sauna, EV charger, kitchen renovation, and garage improvements.
• Replace the existing underground service conductors with a new service installed in conduit.
• Upgrade grounding and bonding as part of the service replacement.
• Add an exterior service disconnect.
• Install whole-home surge protection as part of the new service equipment.
• Coordinate the service upgrade with ComEd, Wood Dale permitting, and required municipal inspections.
• Minimize the homeowner's power outage by completing the underground and exterior work before the final service cutover.
• Restore the concrete, grading, and lawn areas disturbed during underground installation.

The Challenge

The primary challenge was not converting the property from overhead to underground service. The home already had an underground electrical service, but the existing system no longer provided the capacity the homeowners needed.

The original 100-amp, 20-space panel was full and showed corrosion, leaving limited ability to accommodate additional circuits or larger future loads. The existing service also required grounding and bonding upgrades as part of the replacement.

Replacing the underground service required following an approximately 80-foot route from the rear of the house to the existing ComEd pedestal. Portions of the existing service had been buried without conduit, and the new route passed behind a pine tree and beneath a section of the existing concrete patio.

Approximately 3 feet by 16 feet of concrete had to be removed to establish the new underground raceway. The project also required coordination with ComEd for the service upgrade and final cutover. Although active construction required approximately five working days, utility scheduling extended the overall project timeline by nearly three months.

Our Approach

Scope of Work

• Residential electrical load calculation and 200-amp service design.
• Electrical permit drawings and documentation.
• Wood Dale permit and inspection coordination.
• ComEd service-upgrade coordination and scheduling.
• JULIE/811 utility locating before excavation.
• Removal of approximately 3' × 16' of existing concrete to access the underground service route.
• Excavation of an approximately 80-foot underground service trench.
• Installation of 3-inch Schedule 40 PVC underground service conduit.
• Installation of 3/0 copper service conductors.
• Installation of red underground electrical warning tape above the raceway.
• Preparation of service conductors at the existing ComEd pedestal.
• Installation of new 200-amp exterior service equipment and disconnect.
• Installation of a 200-amp Siemens 40-space electrical panel.
• Transfer and labeling of existing branch circuits into the new panel.
• Installation of 35kA surge protection.
• Installation of two new interconnected grounding rods.
• Bonding of the metal water service.
• Bonding at the new service equipment.
• Replacement of the garage feeder with a new 1-inch conduit for future subpanel or EV-charging capability.
• Underground electrical inspection.
• Electrical service inspection.
• Electrical rough inspection.
• Electrical final inspection.
• Building final inspection.
• Coordination of ComEd disconnect and reconnection.
• Concrete replacement over a new gravel base.
• Final grading and lawn reseeding.

Project Outcome

The completed service upgrade increased the home's electrical capacity from 100 amps to 200 amps and replaced the full 20-space panel with a substantially larger 40-space Siemens panel.

The upgraded system provides additional breaker capacity for the homeowners' planned electrical improvements, including a future hot tub, sauna, EV charger, kitchen renovation, garage upgrades, and other expansion.

The existing underground service arrangement was retained, but the approximately 80-foot service run was rebuilt using a new underground conduit system and new service conductors. The new installation also added an exterior disconnect, surge protection, updated grounding and bonding, and clearly labeled transferred branch circuits.

A new 1-inch conduit was also installed for the garage feeder to provide flexibility for a future garage subpanel or EV-charging installation.

Most of the new service infrastructure was constructed before the scheduled utility cutover, limiting the final power interruption to approximately four to six hours. After electrical work and inspections were completed, the removed concrete was repoured, disturbed areas were graded, and the lawn was reseeded.

The homeowner ultimately gained the additional panel and service capacity that prompted the project while also leaving the property better prepared for future electrical improvements.

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