CurrentSpec: Electrical Calculators & Engineering Tools

Deterministic engineering tools for DC conductor sizing, voltage drop, circuit protection, lithium batteries, solar PV strings, and raceway mechanics.

FEATURED CALCULATOR

DC Conductor Sizing & Voltage Drop Calculator

Calculate DC wire size from your actual system voltage, load, cable length and voltage-drop target using a documented engineering reference basis.

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Top Sizers: ☀ MPPT Sizer 🔋 Battery Bank 🛡 DC Fuse Sizer 🛡 Inverter Fuse ⚡ Busbar Ampacity 🚗 EV Charging
Quick Example Interactive Preview
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Enter Values to Calculate

Enter system voltage, load current, cable length, and target drop above to see live sizing recommendations.

Popular & High-Demand Calculators

Quick access to our most accurate, standards-based electrical sizing engines.
View all wire & cable calculators →
Wire & Cable
DC Wire Size & Voltage Drop Sizer
Calculate exact AWG and mm² conductor sizes with embedded reference charts and resistance formulas.
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 Solar PV
MPPT Charge Controller Sizer
Calculate required MPPT output current, cold-weather string Voc limits, and array over-paneling headroom.
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 Battery Storage
Battery Bank Usable Capacity (Ah & Wh)
Size LiFePO4 lithium or AGM battery banks for solar, RV, van, and marine setups based on daily loads.
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 Circuit Protection
Inverter DC Main Fuse Sizer
Calculate DC inverter fuse sizes and AIC fault current ratings comparing Class T, MRBF, and ANL fuses.
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 Circuit Protection
DC Fuse & Breaker Rating Sizer
Size 12V, 24V, and 48V branch circuit protection using the 125% continuous load rule under NEC & ABYC.
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 Advanced Energy
EV Fast Charging Cable Sizer (400V/800V)
Size high-voltage DC conductors and calculate liquid-cooling requirements up to 350kW and 500A.
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 Wire & Cable
Inverter DC Battery Cable Sizer
Size battery cables for 1000W to 5000W pure sine inverters accounting for low-voltage surge.
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 Circuit Protection
Copper & Aluminum Busbar Ampacity
Calculate continuous current ratings, thermal rise, and minimum dimensions for DC distribution bars.
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 Advanced Energy
Wind Turbine Dump Load Resistor Sizer
Size diversion heater resistance in Ohms and continuous Watts to prevent turbine over-speeding.
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 Wire & Cable
Exact DC Voltage Drop & Wire Loss
Calculate exact voltage drop, loop resistance, and continuous line power loss in Watts for custom runs.
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 Conduit & Thermal
Conduit Fill & Raceway Sizer
Calculate raceway fill percentage and minimum conduit trade size per NEC Chapter 9 guidelines.
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 Wire & Cable
DC-DC Charger Dual-Run Cable Sizer
Size primary alternator and secondary auxiliary battery cables for 30A to 60A DC-DC chargers.
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Explore all calculators in each engineering category.
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Wire & Cable
17 calculators
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Protection & Distribution
10 calculators
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Solar & PV
4 calculators
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Battery & Energy Storage
5 calculators
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Vehicle & Off-Grid
10 calculators
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Conversion
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AC & Shore
6 calculators
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Conduit & Thermal
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All 63 Engineering Calculators

Complete index of deterministic electrical sizing and calculation utilities.
⚡ Wire & Cable Hub →
🛡 Circuit Protection Hub →
☀ Solar & PV Systems Hub →
🔋 Battery & Storage Hub →
🚛 Vehicle & Off-Grid Hub →
🔄 Voltage Conversion Hub →
🔌 AC & Shore Power Hub →
🌡 Conduit & Thermal Hub →
🌿 Advanced Energy Hub →
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Practical Engineering Tools for Real-World Systems
These calculators use established engineering references (NEC, ABYC and industry standards) and provide accurate, transparent results based on your actual system values. Each tool includes assumptions, limitations and helpful guidance.
60+ Calculators
Across 9 categories

Engineering Reference & Standards Basis

Calculations are based on standard engineering physics and published electrical references. Voltage drop uses nominal uncoated-copper conductor resistance at 75°C (167°F) per National Electrical Code (NEC) Chapter 9, Table 8. Conductor ampacity references standard ABYC E-11 Table 6B (single conductor in free air with 105°C insulation) and NEC Table 310.16.

This utility is an educational and preliminary sizing reference. It is not system-specific engineering certification or a determination of code compliance. Overcurrent protection calculations explicitly distinguish the calculated sizing basis from final fuse or circuit breaker selection.