Can a duplex have electrical services in two separate locations in washington state if a fire wall seperates the two units
Executive summary
Yes — Washington’s rules and model codes allow separate electrical services for dwelling units where the building is treated as separated by an approved firewall, but the practical answer depends on meeting specific code definitions, utility requirements and local amendments: a minimum two‑hour rated firewall can be considered a building separation under state WAC/NEC references [1], the installing party must consult the serving utility about meter and service location [1], and local jurisdictions may adopt additional electrical code amendments that affect how services are delivered [2] [3].
1. Code backbone — a two‑hour firewall can create a “building separation” for service purposes
Washington’s administrative rules explicitly note that “a firewall must have a minimum two‑hour rating as defined by the local building official to be considered a building separation in accordance with Article 100 NEC” [1], language repeated in state electrical guidance [4], which ties the physical separation to the National Electrical Code’s treatment of separate buildings for service rules.
2. Service location and utility approval are mandatory constraints
The WAC requires the owner, owner’s agent or electrical contractor to consult the serving utility regarding service‑entrance equipment location and meter requirements before installing service and equipment [1], and the serving utility has authority to determine acceptable point of contact for overhead drops and clearances per NEC [1], meaning utility policy can limit whether two separate services/metering points are practically permitted even if the firewall technically qualifies as a building separation.
3. Local codes and city amendments can change the practical outcome
Cities in Washington adopt and amend the NEC and state rules; for example, Bellevue and Seattle enforce updated I‑Codes and NEC editions with local amendments [2] [5], and the Washington Cities Electrical Code provides a framework cities are encouraged to adopt that can supplement or tighten state rules [3]. Therefore whether a duplex receives two separate services can vary by jurisdictional adoption and local code enforcement [3] [2].
4. Installation requirements and accessibility still apply to separate services
Even where two services are allowed, state residential guidance and NEC provisions require service equipment to be located and installed consistent with clearances, accessibility and overcurrent protection rules — electrical panels must be readily accessible and located per NEC restrictions (not in bathrooms, etc.) [6], and overhead service conductor installations must meet conduit and clearance specifications [1].
5. Interpretation and enforcement rest with the local official and utility; plan review advised
The WAC frames the firewall/building separation definition but delegates definition details to the local building official and requires consultation with the serving utility [1], and cities often require plan review and compliance with local amendments to the NEC [5] [2]. State L&I and municipal code pages show ongoing rule review and that electrical rules are periodically updated, so enforcement and requirements can change over time [7] [5].
6. Competing interests and where disputes arise
The technical allowance for separation — a rated firewall meeting the two‑hour threshold — reflects a safety rationale in the NEC and WAC, while utilities and municipalities balance safety, metering logistics, and consistency of service delivery; local codes or utility policies may implicitly prioritize consolidated service for inspection, metering, or operational reasons [1] [3]. When interpretations differ, the local code official, utility requirements, and the adopted city/state electrical code language determine the final answer [1] [3].
Conclusion — what the rule means in practice
A duplex separated by a properly rated two‑hour firewall can be treated as two buildings for electrical service under Washington WAC language tied to the NEC [1] [4], but the installation must satisfy NEC service installation rules, local code amendments, and the serving utility’s meter and service location requirements [1] [6] [3]; therefore the theoretical allowance exists, but the practical outcome requires consultation with local building officials and the utility and adherence to any city‑level electrical amendments [1] [2] [5].