Disclaimer
The DC cable sizing calculator provided on this page is intended as a guide only. Users must understand that the results are based on the inputs given and calculations performed according to the AS/NZS 3008 standard. However, the use of this calculator is at the user’s own risk.
Important Notice: The minimum cable size indicated by the calculator should always be treated as a guideline. It is highly recommended to size up the cable where possible to ensure safety, efficiency, and compliance with local regulations. Factors such as temperature, installation method, and grouping may significantly affect the performance of the cable, and it is the responsibility of the user to account for these considerations.
Always consult a qualified electrician or electrical engineer when determining the appropriate cable size for your specific application.
Method of Calculation
The cable sizing formula utilised in this calculator incorporates key factors as defined by the AS/NZS 3008 standard, including:
- Current (amps)
- Cable length (one-way, adjusted for round-trip)
- Voltage drop percentage
- Conductor material resistivity
- Temperature correction factor
- Grouping correction factor
- Installation method correction factor
The formula used:
Where:
- A = Required cross-sectional area of the cable (mm²)
- I = Current (amps)
- L = One-way cable length (meters)
- ρ= Resistivity of the conductor (Ohms-mm²/m)
- Copper: 0.017241 Ohms-mm²/m
- Aluminium: 0.028264 Ohms-mm²/m
- K1 = Temperature correction factor
- K2 = Grouping correction factor
- K3 = Installation method correction factor
- V = System voltage (V)
- D = Allowed voltage drop percentage
These components ensure that the recommendations provided are aligned with industry standards, though users must apply their judgment and expertise in finalising cable choices.
Understanding the importance of proper cable sizing
Proper cable sizing is crucial in electrical engineering to ensure safe and efficient electrical power transmission. Undersizing a cable can lead to excessive voltage drops, overheating, and potential fire hazards. Conversely, oversizing a cable can increase installation costs and material wastage.
Key features and benefits
- Accurate calculations: The calculator employs precise engineering formulas and industry standards to deliver accurate cable size recommendations.
- User-friendly interface: The intuitive interface makes inputting data and interpreting results easy, even for those without extensive electrical engineering knowledge.
- Comprehensive parameter options: The calculator accommodates various input variables, allowing for precise calculations in diverse electrical scenarios.
- Time-saving efficiency: The calculator significantly reduces the time and effort required for manual calculations by automating the cable sizing process.
- Cost-effective solutions: Proper cable sizing helps optimise material usage and minimise installation costs.
Why use a cable-size calculator?
There are several key benefits to using a cable size calculator, especially for DC applications like:
- Home solar systems: When connecting solar panels to your inverter or battery bank, proper cable sizing is essential to minimise power loss and maximise energy production
- EV chargers: Ensuring your EV charger has the correct cable size guarantees safe and efficient electric vehicle charging.
- Low voltage DC projects: Whether you’re working with battery backups, LED lighting systems, or other DC applications, the calculator helps you determine the optimal cable size for safe and effective operation.
By utilising the Energy Matters DC Cable Sizing Calculator, you can make informed decisions about cable selection and ensure your DC power systems’ optimal performance and safety. Remember, proper cable sizing is not just a technical requirement; it’s a critical factor in the overall efficiency and reliability of your electrical infrastructure.
