Temporary Electrical Service Requirements for Ohio Construction Sites

Temporary electrical service on Ohio construction sites operates under a distinct regulatory framework separate from permanent installations, governed by Ohio-adopted codes, the Ohio Board of Building Standards, and OSHA electrical safety rules. These requirements define how power is supplied, protected, and inspected during the construction phase before permanent systems are energized. Failure to comply with temporary service standards is one of the most frequently cited electrical violations on Ohio job sites, creating both inspection delays and documented injury risk. This page describes the regulatory landscape, structural requirements, applicable scenarios, and the boundaries that determine which rules apply to a given situation.

Definition and scope

Temporary electrical service refers to a power distribution system installed for a limited, defined duration to support construction, renovation, demolition, or maintenance activity. Under the 2023 National Electrical Code (NEC) Article 590, which Ohio has adopted through the Ohio Board of Building Standards (OBC Chapter 4101:8), temporary installations are permitted for the duration of construction work and must be removed upon completion of construction or within 90 days, whichever comes first, unless an extension is approved by the authority having jurisdiction (AHJ).

Scope covers all electrical power and lighting systems installed at a construction site that are not intended to remain as part of the permanent building electrical infrastructure. This includes temporary service entrances, feeder panels, branch circuit distribution, temporary lighting strings, receptacle outlets, and equipment connections.

Not covered under temporary service rules: Permanent electrical installations at active construction sites that are energized for the first time fall under permanent service inspection requirements. Generator-only job sites without a utility connection have overlapping but distinct requirements addressed under ohio-generator-and-standby-systems. Utility service coordination requirements are addressed separately at ohio-electrical-utility-coordination.

For a full treatment of Ohio's broader electrical regulatory structure, see the regulatory context for Ohio electrical systems.

How it works

Temporary electrical service installation on Ohio construction sites follows a sequential process governed by code requirements and the permitting authority of local or state AHJs.

1. Permit application — A licensed Ohio electrical contractor must pull an electrical permit for temporary service installations above a threshold voltage or amperage. Ohio Revised Code §4740.01 et seq. establishes contractor licensing requirements, and the Ohio Construction Industry Licensing Board (OCILB) enforces these standards.

2. Utility coordination — The site contractor contacts the serving electric utility to establish a point of attachment and metering for the temporary service. American Electric Power Ohio, FirstEnergy, or Dayton Power and Light (now AES Ohio) each have published temporary service standards that govern riser height, meter socket specifications, and minimum clearances.

3. Installation to NEC Article 590 standards — Equipment must be listed, conductors must be protected from physical damage, overcurrent protection must be installed at the point of origin, and ground-fault circuit interrupter (GFCI) protection is required on all 125-volt through 250-volt, single-phase, 15- and 20-ampere receptacle outlets (NEC 590.6(A)). The 2023 NEC also continues to require GFCI protection for temporary wiring used on construction sites, with no relaxation of those requirements from the 2020 edition.

4. Inspection — The AHJ inspects the temporary service installation before energization. In Ohio, the AHJ may be the local building department, a state fire marshal inspector, or the Ohio Department of Commerce Division of Industrial Compliance depending on the project type and jurisdiction. The ohio-electrical-inspection-process page covers inspection sequencing in detail.

5. Duration and removal — Temporary service must not exceed 90 days unless extended by the AHJ. At project close-out, the temporary service must be disconnected and removed before final occupancy inspection of the permanent system.

OSHA 29 CFR 1926 Subpart K (OSHA 1926.400–1926.449) establishes additional electrical safety standards for construction that run parallel to NEC requirements and are enforced independently by Ohio OSHA under a state plan approved by federal OSHA.

Common scenarios

New commercial or industrial construction — High-amperage temporary services, typically 200A to 400A three-phase, are established at the utility's transformer or an overhead service drop. Feeder panelboards are positioned throughout the site as construction progresses floor by floor.

Residential subdivision development — Individual lots often share a single temporary service pole for the early phases of framing, then individual temporary services are established per unit. Temporary service poles must meet the utility's minimum burial or riser specifications.

Renovation of occupied buildings — Where the permanent service must be de-energized temporarily, a separately metered temporary feed maintains power to tenant areas not under active construction. This scenario requires careful circuit segregation to prevent code violations on the active-occupancy side.

Demolition projects — Power is required for lighting, tools, and dust control equipment, but load requirements are substantially lower than new construction. NEC 590 GFCI and cord protection standards apply equally regardless of project type.

Seasonal or event construction — For temporary structures such as fairgrounds, seasonal entertainment facilities, or tent installations, Article 590 time limits are directly relevant. Installations exceeding 90 consecutive days shift into permanent-installation classification under the code.

Decision boundaries

The primary classification boundary is duration: installations under 90 days qualify as temporary under NEC Article 590; installations intended to exceed 90 days require permanent installation methods unless the AHJ grants an extension in writing.

A second boundary separates service-entrance-level temporary power (requiring utility coordination and an electrical permit) from cord-and-plug-connected temporary equipment (covered by OSHA 1926 tool and equipment rules but not requiring a separate permit). A temporary panelboard fed by conductors from a utility meter is the former; a generator with extension cords serving only hand tools is the latter — though both must comply with GFCI requirements.

A third boundary involves voltage class: installations above 1000 volts nominal (medium voltage temporary feeds for large industrial construction) fall outside standard NEC Article 590 and are governed by NEC Article 590 in conjunction with Articles 225 and 230, as well as the requirements of the serving utility's interconnection standards. Note that the 2023 NEC updated the voltage threshold terminology from "600 volts" to "1000 volts" in relevant sections, reflecting the code's broader realignment with international standards.

The ohio-electrical-authority-jurisdictions page maps which AHJ has permitting authority on a given Ohio site — a determination that varies significantly between state-licensed facilities (hospitals, schools) and municipally permitted commercial projects. For the full interconnected landscape of Ohio electrical systems and compliance obligations, the main Ohio electrical authority index provides the broader reference framework.

Grounding and bonding of temporary service equipment follows NEC Article 250 without modification for temporary status — temporary installations do not receive any grounding exemption. Specific grounding requirements are detailed at ohio-grounding-and-bonding-requirements.

References

• National Electrical Code (NEC) NFPA 70, 2023 Edition, Article 590 — Temporary Installations
• Ohio Administrative Code Chapter 4101:8 — Ohio Building Code, Electrical Provisions
• Ohio Revised Code Chapter 4740 — Electrical Contractors
• Ohio Construction Industry Licensing Board (OCILB)
• Ohio OSHA — Division of Industrial Compliance
• OSHA 29 CFR 1926 Subpart K — Electrical Safety in Construction
• Ohio Board of Building Standards