Example field question
Use this calculator when a design review or site issue requires a quick engineering check before a detailed manufacturer selection.
VoltCheck24 Engineering Calculator
DC Cable Size Calculator for Battery, Solar, and Control Wiring
Estimate DC cable size for battery, solar, control panel, and low-voltage equipment wiring using current, distance, and voltage-drop limits.
How to use this calculator
- Collect the values below from the equipment nameplate, data sheet, or field measurement.
- Enter values using one consistent unit system and use worst-case operating conditions.
- Review the result, margin, and engineering note before selecting hardware.
- Cross-check the result with the related calculator and save the review for your project record.
Input checklist
- Cable route length
- Load current and duty cycle
- Installation temperature and grouping
- Fuse or breaker rating
Common mistakes to avoid
Do not mix nominal values with measured worst-case values. Keep units consistent and include cable, temperature, duty, and derating assumptions where applicable.
Standards and validation
Review the result against local codes, IEC/NEC/NFPA/ISO practices when applicable, project specifications, and the latest manufacturer data sheet.
Formula and Inputs
Cable voltage drop is calculated from conductor resistance per length, round-trip path length, and operating current.
Industrial Use Cases
Use this calculator for panel feeders, DC branch circuits, battery devices, lighting, instrumentation, and small motor loads.
Engineering Note
For final cable selection, verify short-circuit protection, terminal temperature rating, insulation type, grouping derating, and local wiring rules.
DC wire sizing workflow for global projects
DC wiring problems usually start with a simple question: will the load still receive enough voltage after current flows through a long conductor? VoltCheck24 treats wire size as a voltage-drop and verification workflow, not only a gauge lookup. Start with the real load current, one-way route length, system voltage, and acceptable voltage drop. Then compare the result with ampacity, fuse or breaker size, terminal limits, insulation temperature, and local code requirements.
DC source+Supply conductor resistance+Load current=Terminal voltage margin
| Use case | Common search intent | What to verify after voltage drop |
|---|---|---|
| 12V battery, RV, marine, LED | 12V wire size calculator, battery cable size | Fuse location, flame rating, vibration, wet or outdoor environment |
| 24V PLC, sensor, solenoid, IO-Link | 24V cable calculator, sensor voltage drop | Device minimum voltage, inrush current, shared returns, SMPS tolerance |
| Solar DC and off-grid wiring | solar DC cable size calculator, PV voltage drop | UV rating, connector current, temperature derating, PV code rules |
| International panel wiring | AWG to mm2, wire size calculator DC | AWG/mm2 conversion, terminal range, IEC or NEC project standard |
Important: voltage-drop calculators support preliminary sizing only. Final conductor selection must be checked against the latest local electrical code, manufacturer data sheets, protection coordination, and measured field conditions.
Battery, solar, and control cable sizing
Use this page when cable construction and installation environment matter in addition to voltage drop. Add fuse, insulation, outdoor, temperature, and connector checks after the calculation.
Worked field question: Example: a battery-to-controller run with a known peak current. Use the worst-case route length and verify both conductors, not only the positive lead.
FAQ
Is cable size the same as wire size?
In search language they are often used together. Practically, cable selection also includes insulation, sheath, installation environment, and number of conductors.
Can I use this for AC cable sizing?
This page is focused on DC voltage drop. AC systems may need impedance, power factor, phase configuration, and local code checks.
Preliminary engineering reference only. Confirm final selections against current standards, project specifications, and manufacturer data.