Electrical estimating measures and prices distribution equipment, feeder and branch wiring, lighting, devices, grounding, conduit, low-voltage systems, and supporting work. Quantities come from electrical plans, schedules, specifications, and riser diagrams. Labor depends on installation conditions, access, trade sequencing, and the contractor's crew assumptions.
Start with the service and distribution design
Read the one-line diagram, panel schedules, riser diagram, and utility coordination notes. The service entrance, switchgear, transformers, main panels, subpanels, and metering define the distribution backbone. Each has equipment, conduit, feeder, grounding, and connection requirements that do not appear on the floor plan alone.
Coordinate utility provider requirements with the design team before pricing the service entrance. In Arizona, APS, SRP, and TEP serve different territories and have different connection standards that can affect the project scope.
Branch wiring and device counts
Floor plans show circuit layouts, device types, and outlet locations. Specifications define device grades, colors, and installation requirements. Reconcile both before building the takeoff.
Count devices, fixtures, and equipment connections from the architectural and electrical plans together. An architectural plan may show more outlets than the electrical drawings schedule — or the reverse. Treat that difference as a clarification item, not a silent selection.
Measure conduit, not just circuits
Conduit quantity depends on routing, size, material, support spacing, and the number of conductors. An apparent circuit run can require more conduit than the straight-line distance suggests. Raceways in walls, above ceilings, underground, and in exposed areas require different materials and methods.
Keep conduit material types separate. EMT, rigid steel, rigid PVC, and liquid-tight flexible conduit serve different conditions and have different costs. Confirm the specification requirements and routing assumptions before summarizing.
Low-voltage systems need separate scope definition
Data, telecom, audio-visual, fire alarm, security, CCTV, and building automation may appear in electrical drawings or may be separate packages. Assign each system explicitly. The phrase 'complete electrical' does not automatically include low-voltage systems.
For MEP estimating, a responsibility matrix makes these boundaries visible to all trades. Confirm who supplies conduit, pulls cable, terminates, tests, and commissions each low-voltage system.
Arizona service territory and coordination considerations
Arizona's primary electric service providers — APS (Arizona Public Service) in the Phoenix metro and most of central Arizona, SRP (Salt River Project) in parts of the Phoenix metro, and TEP (Tucson Electric Power) in the Tucson area — have different coordination requirements for temporary power and permanent service connections.
Service coordination timelines can affect project scheduling. An estimator should identify the responsible party for utility design, coordination, fees, and connection work. Confirm which costs belong in the construction estimate and which are owner responsibilities.
Example: a commercial tenant improvement
A hypothetical Chandler office tenant improvement adds private offices, a server room, and an upgraded kitchen. The electrical estimate should separate the panel capacity check, new circuit runs, lighting layout, device changes, dedicated circuits, server-room power, and kitchen equipment connections.
Each section may require different conduit, wiring, and coordination work. Adding all of it to a single electrical allowance would prevent the contractor from identifying which part of the scope is driving cost.
Questions, clarified.
Does electrical estimating include fire alarm?
Only when explicitly agreed. Fire alarm is often a separate specialty package with its own designer, installer, and AHJ review. Confirm whether it is in the electrical scope or a separate contract.
What drawings are needed?
Electrical plans, one-line diagram, panel schedules, lighting schedules, riser diagram, specifications, and any low-voltage system documentation. Include architectural and MEP plans for coordination.
Are utility fees included?
Utility connection fees, meter deposits, and coordination costs may be owner-paid items excluded from the contractor's scope. Identify them in the scope matrix rather than assuming they are in the electrical bid.
How are temporary power costs estimated?
Identify the power source, distribution, transformer, panel, branch circuits, and duration. Temporary power can be a general-conditions item or assigned to a lead contractor. Agree the scope before the project starts.
Can solar or PV systems be included?
Only when supported by design documents and confirmed as within the team's scope. Photovoltaic systems, interconnection, metering, and utility approval involve specialized scope distinct from standard building electrical.