Electrical Service Entrance Requirements in Ohio

The service entrance is the point at which the electric utility's distribution system connects to a building's internal wiring — a junction governed by both utility standards and adopted electrical codes. In Ohio, this intersection is subject to requirements from the local authority having jurisdiction (AHJ), the serving electric utility, and the Ohio Board of Building Standards. Compliance failures at the service entrance carry consequences ranging from refused utility connection to failed inspections and potential fire hazard classifications under NFPA 70 (the National Electrical Code).

Definition and scope

The service entrance comprises three primary components: the service drop or lateral (the utility's conductors), the service entrance conductors (the wiring between the utility attachment point and the meter), and the main service equipment (the meter base, main disconnect, and distribution panel). Each component sits within a distinct ownership and regulatory boundary.

Ohio adopts the National Electrical Code through the Ohio Board of Building Standards, which publishes the current Ohio Building Code. As of the 2023 Ohio Building Code cycle, the state has adopted the 2020 edition of NFPA 70 with Ohio-specific amendments; however, NFPA 70 has since been updated to the 2023 edition (effective 2023-01-01), and practitioners should verify whether the AHJ or Ohio Board of Building Standards has incorporated the 2023 edition into its current adoption cycle. AHJs — including municipal building departments and county inspection offices — may apply additional local requirements on top of the state baseline.

Scope boundary: The requirements addressed here apply to service entrances within Ohio's jurisdiction for buildings regulated under the Ohio Building Code. Utility-side infrastructure (poles, transformers, primary conductors) falls under the jurisdiction of the serving electric utility and the Public Utilities Commission of Ohio (PUCO). Federal installations, tribal land structures, and certain federally regulated facilities are not covered by Ohio's AHJ authority. For broader regulatory framing applicable to Ohio electrical systems, see Regulatory Context for Ohio Electrical Systems.

How it works

A service entrance installation follows a structured sequence of regulatory checkpoints:

1. Pre-application coordination — The property owner or licensed electrical contractor contacts the serving utility to obtain the utility's specific service entrance requirements, including approved meter base configurations, conductor sizing, and clearance specifications. Ohio's major investor-owned utilities (AEP Ohio, FirstEnergy/Ohio Edison, Duke Energy Ohio, AES Ohio) each publish their own service guides.
2. Permit application — A permit is pulled from the local AHJ before installation begins. Ohio Revised Code Chapter 3781 establishes the framework for building permits and inspections for electrical work.
3. Conductor and equipment sizing — Service entrance conductors are sized under NEC Article 230 based on calculated load (ohio-electrical-load-calculations). Residential services in Ohio are most commonly installed at 200-ampere capacity, though 400-ampere services are required for larger homes and added EV charging or HVAC loads.
4. Physical installation — Installation must comply with NEC Article 230 clearances: a minimum 10-foot clearance above finished grade for service drops over pedestrian areas, 12 feet over residential driveways, and 18 feet over public roads (NFPA 70, Article 230.24, 2023 edition).
5. Rough-in inspection — The AHJ inspects the service entrance before the meter base is enclosed and before the utility makes its final connection.
6. Utility connection authorization — Once the AHJ approves, the utility receives notification and schedules the connection. No utility in Ohio is obligated to connect an unapproved installation.
7. Final inspection — After energization, a final inspection closes the permit.

Grounding and bonding at the service entrance is governed by NEC Article 250. The grounding electrode system, which includes ground rods, the metal water pipe (where applicable), and the concrete-encased electrode (Ufer ground), must be bonded at the service disconnecting means. For detailed grounding requirements, see Ohio Grounding and Bonding Requirements.

Common scenarios

New residential construction: A new single-family home typically requires a 200-ampere, 120/240-volt single-phase service. The utility specifies the meter base type (ringless or ring), and the contractor installs a service entrance cable (Type SE or USE-2) or conduit-based system per the AHJ's preference. Panel placement must allow the required working clearance of 36 inches in depth, 30 inches in width, and 6.5 feet in height per NEC 110.26.

Service upgrade on an existing structure: Upgrading from a 100-ampere to a 200-ampere service on an older home involves permit filing, replacement of the meter base and main panel, and often replacement of service entrance conductors. Ohio inspectors frequently cite inadequate conductor sizing and missing grounding electrode conductors as violations. For upgrade-specific considerations, see Ohio Electrical Panel Upgrades.

Underground (lateral) service: Where utilities are buried, the service lateral transitions to a service entrance at a meter base mounted on the structure or a pedestal. Conduit burial depths follow NEC Table 300.5: 24 inches minimum for RMC/IMC, 24 inches for PVC under general conditions, and 18 inches under a concrete slab. Underground services require inspection of the conduit installation before backfill.

Commercial and multifamily: Commercial services frequently operate at 120/208-volt or 277/480-volt three-phase configurations. Service entrance equipment for commercial occupancies must include proper interrupting ratings matched to the available fault current from the utility. For multifamily configurations, see Ohio Electrical Multifamily Requirements.

Decision boundaries

The following distinctions determine which requirements apply and who must perform the work:

Licensed contractor requirement: Under Ohio Revised Code §4740, electrical work on service entrances must be performed by a licensed electrical contractor or under the supervision of one. Homeowner exemptions under Ohio law are narrow and do not extend to utility-coordinated service entrance work in most AHJ jurisdictions. Licensing classifications and qualification standards are detailed at Ohio Electrical Licensing Requirements.

AHJ authority vs. utility authority: The AHJ controls code compliance on the customer side of the meter. The utility controls the meter base configuration, service lateral, and final connection approval. A conflict between utility requirements and NEC provisions is resolved in favor of the utility for the utility-owned portion, and in favor of the NEC/AHJ for everything on the customer side. This division is addressed further on the Ohio Electrical Authority site index.

Overhead-to-underground conversions require coordination with both the AHJ (for the new lateral's conduit and backfill inspection) and the utility (for scheduling the cut-over and any required equipment change at the transformer). Projects involving solar generation interconnection add a third layer of review through the utility's interconnection process — see Ohio Solar Electrical Interconnection.

References

• Ohio Board of Building Standards — Ohio Building Code
• NFPA 70: National Electrical Code (2023 edition, free access)
• Public Utilities Commission of Ohio (PUCO)
• Ohio Revised Code §4740 — Electrical Licensing
• Ohio Revised Code Chapter 3781 — Building Standards and Inspections
• AEP Ohio — Electric Service Requirements
• FirstEnergy / Ohio Edison — Service Information