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DC Cable Sizing Tool - Use The Correct Sized Cables - Free Calculator

This online cable size calculator tool makes it easy to establish the correct size of cables for any DC power system. 

Cable sizes are particularly important for low voltage battery cables, solar panels, wind turbines and load cables. Voltage loss or drops through incorrectly sized cables are one of the most common reasons for low voltage (12V, 24V or 48V) system faults.

If the cable is too small, it can be very dangerous as the cable will heat up and potentially cause a fire. Undersized cables also waste energy. Conversely, too large a cable and you are simply wasting your money on good copper.

cable size is vital on low voltage systems                        
How To Use The Cable Size Calculator


1 - Enter percentage cable loss acceptable  [normally approx 2 or 3%].

2 - Enter nominal system voltage  [or pv array voltage for solar cables].

3 - Enter max amps to be carried by the cable  [amps = watts / voltage].

4 - Enter length of cable run required  [power source to load].

5 - Click "Calculate" - results are shown in the closest standard metric & AWG cable sizes.



All cable sizes given on this page refer to single core HO7RNF rubber insulated cable, at an ambient temperature of 30 deg C, and a conductor temperature of 85 deg C max.

Cable sizes should only be used as a guideline and if not using HO7RNF cable, all figures should be checked against the manufacturers data sheet. Also, all cables should be fused / current protected to their max rating or less.

Disclaimer : We (www.solar-wind.co.uk) accept no legal liability for any issues caused by using this cable sizing calculator.

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