Electrical raceway calculation tools

Clear code referencesInstant pass/fail validationProfessional PDF reporting

This tool is free to use while I keep building, improving, and adding more helpful features behind the scenes. If you enjoy using it, feedback and support are always appreciated!

Support

Quick Select Popular Calculators

See Calculator List for all calculators.

Disclaimer: RacewayIQ is an informational engineering tool only. All calculations must be independently verified by the user. Do not rely on these results as the sole basis for design, procurement, installation, construction, permitting, or code compliance decisions.

Conduit fill and raceway capacity

Conduit Fill Calculator

Enter raceway and conductor or cable area information, then compare installed area against selected code-reference fill limits.

Project and Raceway Setup

Project nameLocationPrepared byDateUnitsConduit type/materialSelect the actual raceway type because internal area changes by material and schedule.Conduit trade sizeUse the installed or proposed trade size; the calculator uses its listed internal area.

Cable and Conductor Groups

Group 1

NameExample: phase conductors, grounding conductor, control cable, or fiber cable.Cable/conductor typeUse for documentation, such as THHN, XHHW, MC cable, or manufacturer cable type.QuantityNumber of conductors or cables of this same size/type in the raceway.Cable Measurement TypeUse outside diameter when the datasheet gives diameter; use area when the datasheet gives area.Outside diameter (in)Enter one conductor or cable maximum outside diameter from manufacturer data.

Result

EMT - Electrical Metallic Tubing, trade size 1

Pass

Previous valid result shown. Fix input errors before calculating.

Internal area

0.8640 in2

Allowable fill

40%

Allowable area

0.3456 in2

Installed area

0.1473 in2

Actual fill

17.04%

Remaining area

0.1983 in2

Additional similar fit

Save and Export

Fix input errors before calculating.

I understand this report is for informational design assistance only and must be independently verified before use.Check this box to enable PDF export.

Save: Fix input errors before saving.

Export: Create a free account and check the acknowledgement box to export PDF reports.

Save to Project Schedule (Beta)

Add this conduit fill result to the project schedule (Beta). RacewayIQ will create or update a conduit item and save the cable/conductor set with it.

Open Schedule (Beta)

Schedule action

Conduit TagDescriptionFromToLocationInstallation AreaLength (ft)Notes

Cable/conductor set from this calculation

These conductors will be saved with the conduit run automatically.

3 x Left blank Left blank

Calculation Breakdown

Total conductor count: 3. Chapter 9 Table 1 allowable fill: 40%.

Allowable fill area = 0.8640 in2 x 40% = 0.3456 in2.

3 x Left blank: area = pi x (OD / 2)^2 for 0.25 in; group area = 0.1473 in2.

Actual fill = installed area / total conduit area x 100 = 17.04%.

Remaining available area = allowable fill area - installed area = 0.1983 in2.

Code References

NEC Chapter 9, Table 1

Percent of cross section of conduit and tubing permitted for conductors and cables: 53% for one conductor, 31% for two conductors, and 40% for more than two conductors.

Config note: Update when local amendments or future editions alter fill percentages.

NEC Chapter 9, Table 4

Dimensions and percent area of conduit and tubing. This app stores conduit internal areas by material and trade size in a replaceable data module.

NEC Chapter 9 Notes

Apply notes and exceptions for cable assemblies, nipples, compact conductors, and installations with special conditions where applicable.

Electrical raceway calculation tools

Quick Select Popular Calculators

Conduit Fill Calculator

Project and Raceway Setup

Cable and Conductor Groups

Group 1

Practical electrical calculators

Core Raceway

Conductors & Feeders

Power Distribution

Communications

Planning & Estimating

Step-by-step electrical workflows