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Free Engineering Calculators

NEC 2023 and CEC 2024 compliant calculators for everyday electrical engineering tasks — powered by the same engine as the full EEP platform. Create your free Beta account to run any tool below; viewing the layout is open to everyone.

Advisory only. Results require PE review per NEC ASM-007 / CEC Rule 2-030.

NEC Cable Sizing Calculator

FREE-001 — NEC 2023 T310.16 / T310.15(B)(1) / T310.15(B)(2)(a) / 240.4(D) / 110.14(C)

Design Current (A)

Load Type

Conductor Material

Installation

Temp Rating

Ambient Temp (°C)

No. of CCC

System Voltage (V)

Enter parameters and click Calculate to see NEC conductor sizing results with step-by-step code trace.

Cable Pulling Calculator

FREE-002 — NFPA 70 300.17 / NECA 101

Conduit Trade Size

Conduit Type

Total Length (ft)

Friction Coefficient μ

Number of 90° Bends

Number of 45° Bends

Cable Weight (lb/ft)

Cable OD (inches)

Enter conduit and cable parameters to calculate pull tension, jam ratio, and NFPA 70 300.17 compliance.

Arc Flash Incident Energy

FREE-003 — IEEE 1584-2018 (simplified) / NFPA 70E-2021 T130.7(C)(15)(a)

System Voltage (V)

Bolted Fault Current (kA)

Working Distance (in)

Clearing Time (cycles)

Equipment Type

Enter system parameters to calculate arc flash incident energy, flash protection boundary, and NFPA 70E PPE category.

Maximum Demand Calculator

FREE-004 — NEC Art. 220 / T220.42 / T220.44 / 220.82

Occupancy Type

Floor Area (sq ft)

Load Items

Add loads and click Calculate to determine maximum demand, demand factors, and recommended service size per NEC Art. 220.

Protection Coordination Check

FREE-005 — NEC 240.12 / IEEE Std 242 (Buff Book) / NFPA 70E

Upstream Breaker Rating (A)

Downstream Breaker Rating (A)

Max Fault Current at Downstream (kA)

Load Current (A)

Enter upstream and downstream breaker ratings with fault current to assess basic selectivity coordination.