THE ELECTRICIANAMERICAN FIELD TOOLS · WORKS OFFLINE
BUILT FOR THE FIELD

THE ELECTRICIAN.
TOOLS THAT WORK.

American-inspired field tools for the people who keep the power on. Straight answers for the service truck, jobsite, and panel room.

126 circuit positions
3 voltage presets
4 field tools
0 internet needed once opened
Field calculations are preliminary, not a permit or engineering approval. Check the actual equipment, installation conditions, and locally adopted code. Texas adopted the 2026 NEC effective September 1, 2026; the calculators use common reference data, and project-specific 2026 requirements still must be verified.
TOOL 01 / CIRCUIT LOOKUP

Circuit Color Finder

Type a circuit number or range, or tap the panel. All 126 circuits change with the voltage setting.

Choose the panel system

Look up a circuit

Your results

1 circuit

Phase identification: These colors are common US conventions, not a guarantee of actual installed colors. Confirm the panel schedule, measured voltages, panel bus phasing, circuit identification, and on-site color rules. This does not model 120/240V high-leg delta. Neutral is generally white on 120V systems, gray on a 277V system; equipment grounds are green or bare where applicable.

126-circuit panel

Odd on the left, even on the right. Tap breakers to add or remove them.

For 120/240V single-phase, paired breakers alternate A/B. Three-phase paired breakers cycle A/B/C. Your actual panel may have different numbering or arrangements.
TOOL 02 / BENDING MATH

Conduit Bending

Fast layout math for stub-ups, two-bend offsets, and three-bend saddles. All dimensions are in inches; use decimal or fractional inches (like 3 1/2).

90° stub-up

Arrow mark = finished stub height − the bender's take-up (deduct).

Typical starting deductions: 1/2″ = 5″, 3/4″ = 6″, 1″ = 8″, 1-1/4″ = 11″. Always check the stamped shoe/brand. Exact arrow marks vary by bender.
ARROW MARKSTUB
A minimum length and bender-to-bend clearance still apply. Mark orientation, bend radius, springback, and conduit type can affect the finished fit.

Two-bend offset

Two equal and opposite bends. Mark spacing = height ÷ sin(angle). Calculated shrink uses ideal bend-centerline geometry; bend radius changes real-world results.
MARK SPACINGRISE

Three-bend saddle

Uses common 22.5° / 45° / 22.5° layout. The center mark is placed at the obstacle center plus the estimated shrink compensation; outer marks lie equally on each side. Verify bending order, shoe references and actual springback.
OBSTRUCTION
Bending layout is a field aid, not a substitute for the actual bender instructions. Check bend-radius limits, cumulative bends (typically 360° maximum between pull points), and the equipment's bending marks before cutting conduit.
TOOL 03 / LOAD-BASED WIRE SIZING

Wire Sizing

Choose the job, the load, and actual installation conditions. See ampacity-only and voltage-drop sizes, plus the limiting factors behind each result.

Quick starting points
01 / LOAD

What are you feeding?

General circuits use noncontinuous amperes + 125% of the continuous portion. MCA values already reflect the equipment sizing rules—do not apply 125% twice. For kW, enter power factor; kVA already includes apparent power.

02 / WIRE AND INSTALLATION

Installation details

Only count conductors that actually carry current. Grounds do not count for ampacity adjustment; some neutrals do. The breaker check is intentionally conservative and does not apply next-size or special equipment exceptions.

03 / RUN AND VOLTAGE DROP

Run information

Based on common NEC Table 310.16 ampacities and 310.15 temperature / conductor-count adjustments. Verify actual insulation markings, terminal listings and the locally applicable 2026 NEC before choosing wire. Wet location THHN must also be marked with an appropriate wet-location rating such as THWN-2.
YOUR RESULT

Preliminary wire selection

Important safety limitations. This is a preliminary single-conductor, raceway-based estimate, not an engineering approval. Do not use generic branch/feeder sizing for motors (Article 430), HVAC MCA/MOCP (Article 440), service sizing (Article 230/310.12), EV charging, or other special circuits without the applicable rules. No parallel sets, NM cable-specific rules, rooftop heat adder, harmonics, transformer secondary rules, or equipment grounding sizing are modeled. Voltage drop is approximate, not AC impedance modeling.
Field tip: 100% continuous loads on standard 80%-rated breakers generally require 125% load sizing. For any 100%-rated assembly exception, verify the actual listed equipment and the applicable rule.
TOOL 04 / RACEWAY AREA

Conduit / Wire Fill

Add groups of conductors with different sizes. Get total occupied area, percent fill, and a suggested conduit trade size.

Raceway and wires

Wire groups

Count every conductor occupying the raceway, including grounds. Add another group for a different wire size; insulation type applies to all groups.

This calculator covers individual round insulated conductors, not NM/MC cable assemblies, mixed insulation types within one group, bare grounds, compact stranding, conduit bodies, cable tray, or flexible raceways. Verify exact insulation dimensions/manufacturer, code tables, and any special fill rules.

Fill results

A pass on physical fill does not mean ampacity passes. Derating for multiple current-carrying conductors, heat, neutral counting, 310.15 conditions, pull difficulty, and raceway installation limits are separate.