Electrical Takeoff Guide: Counting Devices, Conduit, Wire, and Gear

An electrical takeoff is the foundation of every electrical bid. This guide walks through how to do electrical takeoff the right way — reading one-lines, counting devices, sizing conduit and wire, and using AI electrical takeoff tools to move faster without missing anything.

What Is Electrical Takeoff

An electrical takeoff is a complete list of every device, fixture, foot of conduit, foot of wire, box, termination, and piece of gear required to light and power a building. It is the input that feeds the bid pricing. A good takeoff makes pricing easy. A sloppy takeoff means guessing.

Unlike drywall, where you mostly count square feet, electrical quantity takeoff is a mix of counting (devices, fixtures, panels) and measuring (conduit, wire, feeders). The mix is what makes it hard.

Why it matters

Electrical subcontractors often run 3–6 percent net profit. A 2 percent error in quantities or pricing can wipe out the job. Getting the takeoff right is the single most important thing a junior estimator can learn.

Reading Electrical Plans

Every electrical drawing set has a pattern. If you read them in the right order, the takeoff flows naturally.

Sheet order

1. E0.1 Legend and symbols — your decoder ring. Every device symbol lives here.
2. E0.2 General notes and specifications — mounting heights, conduit type, wire type.
3. E1-series Power plans — receptacles, equipment connections, panel locations.
4. E2-series Lighting plans — fixtures, switching, emergency.
5. E3-series Systems plans — fire alarm, data, security.
6. E4-series One-line diagrams — the power flow map.
7. E5-series Panel schedules — every circuit, every breaker.
8. E6-series Details and riser diagrams — connection specifics.

The specifications

Division 26 (formerly 16) of the specs tells you wire type (THHN, XHHW, MC), conduit type (EMT, IMC, RGS, PVC), fixture manufacturers, panelboard requirements, and testing. When plans and specs disagree, specs usually control. Read Division 26 before you count a single receptacle.

Counting Devices

Devices are the easiest thing to count and the easiest to get wrong because there are so many.

Common device categories

• Receptacles — duplex, GFCI, USB, isolated ground, quad, 20A, 30A, 50A.
• Switches — single pole, 3-way, 4-way, dimmer, occupancy sensor, keyed.
• Data/voice jacks — CAT6, CAT6A, fiber.
• Floor boxes — power, data, AV.
• Special purpose — motor disconnects, pool/spa GFCIs, AFCIs.

How to count

Open the legend and list every symbol. Then on each floor plan sheet, count each symbol one at a time. A device count worksheet organized by room makes verification easy. Most mistakes come from missing exterior receptacles, mechanical room convenience outlets, and special purpose devices like fridge plugs or dishwasher boxes.

Lighting Fixtures

The lighting plans show every fixture with a letter or number tag (A1, F2, P6). The lighting fixture schedule lists manufacturer, catalog number, lamp type, wattage, voltage, and mounting.

What to take off

• Fixture count by type.
• Emergency / egress fixtures (usually labeled with "E" or shaded).
• Exit signs (count as their own category).
• Occupancy / daylight sensors.
• Lighting controls and relay panels.
• Drivers, ballasts, and accessories (if not included in fixture pricing).

Switching and controls

Trace each switch leg from switch to fixture. Commercial projects increasingly use addressable lighting controls (0-10V, DALI, DMX) — each of those adds cabling and commissioning cost. Call it out separately.

Conduit and Raceway

Conduit types

• EMT — Electrical Metallic Tubing. Standard for interior commercial above ceiling.
• IMC — Intermediate Metallic Conduit. Heavier than EMT, used where protection is needed.
• RGS / RMC — Rigid galvanized. Exterior, wet, or hazardous locations.
• PVC (Schedule 40 / 80) — Underground and wet locations.
• MC Cable — Metal-clad cable, often used in place of conduit + wire for branch circuits.
• Flexible conduit (Greenfield, Liquid-tight) — Final connection to motors and equipment.

Measuring conduit

Trace each run on plan. Add these allowances:

• +10-15 percent for bends, offsets, and routing around obstructions.
• +8-10 ft per drop to a ceiling-mounted device from above-ceiling.
• +4-6 ft per drop to a wall device from above-ceiling.
• Vertical runs — use actual riser dimensions from sections.

Conduit fill

Check NEC Chapter 9 Table 1 for maximum fill (usually 40 percent for 3+ conductors). Size the conduit to fit the wire. If the plans spec too-small conduit for the called-out wire, bid the correct size and submit an RFI.

Wire and Cable

Wire types

• THHN/THWN — Standard insulated copper, 90°C, dry and wet.
• XHHW — Cross-linked polyethylene, 90°C wet.
• MC Cable — Metal-clad, pre-assembled for branch runs.
• Service entrance (SER, SEU) — For service feeders.
• Aluminum (XHHW-2) — Large feeders where spec allows.

Measuring wire

For branch circuits, multiply conduit length by number of conductors in the conduit. A 100 ft run of 3/4 in. EMT with 2 #12 + 1 #12 GND = 300 linear feet of #12 wire. For feeders, use the panel schedule to get conductor count and size, then measure the one-line route.

Wire allowances

• Add 5-10 percent waste on branch circuits.
• Add 2-3 ft per device for terminations and slack.
• Add 8-12 ft per panel for pull, make-up, and termination at panels.

Panels, Gear, and Transformers

From the one-line

The one-line diagram gives you the complete gear list. Take off:

• Service entrance equipment — CT cabinet, meter, main disconnect.
• Switchboards and switchgear.
• Transformers (dry-type, pad-mount).
• Panelboards (by voltage, amperage, and number of circuits).
• Generator, ATS, UPS (if in scope).
• Motor control centers and VFDs.

Panel schedule verification

Always cross-check the one-line against the panel schedule. If the one-line says 225A and the schedule says 400A, something is wrong. Send an RFI. Pricing the wrong panel can cost $5,000+ per mistake.

Fire Alarm and Low Voltage

Fire alarm takeoff

Per NFPA 72, fire alarm systems include:

• Smoke and heat detectors.
• Manual pull stations.
• Horn/strobes (notification appliances).
• Speakers for voice evacuation.
• Monitor and control modules.
• Fire alarm control panel (FACP) and remote annunciator.
• Battery backup.

Data and AV

Structured cabling (Cat6, Cat6A, fiber) is usually 25-50 ft per drop for the horizontal plus backbone. AV systems are highly custom — get the vendor's BOM instead of guessing. Always confirm if low-voltage is in or out of the electrical scope; it is the biggest scope dispute in the trade.

AI Electrical Takeoff

Electrical takeoff has always been the slowest trade takeoff because of the sheer number of items. AI electrical takeoff platforms like PILRS automate the repetitive work:

• Read the symbol legend and auto-count every device across the sheet set.
• Trace conduit runs using the panel schedule and one-line logic.
• Size wire from the panel schedule automatically.
• Flag scope gaps (missing panel schedules, unlabeled devices).
• Output a bid-ready list with NECA labor units attached.

What AI still misses

• Job conditions (height, congestion, schedule pressure).
• Owner-furnished vs contractor-furnished items.
• Scope gray areas between trades.
• Addenda revisions that are not on the base drawings.

The best electrical estimating software pairs AI takeoff with a human estimator's judgment.