What Gauge of Wire to use with a 1,500 watt Inverter?

If you’ve plans to build an off-grid solar system that uses a 1,500-watt inverter, you need to know the recommended gauge of wire to use for the inverter to use safely and for it to work reliably.

The recommended wire size information may not be readily available for several reasons – perhaps there’s no documentation to refer to, or the lengths your plan to use are longer than what the manufacturer provides.

If this is you then read on to find what gauge of wire you can use for a 1500-watt 12V / 24-volt inverter to work both safely and reliably and the fuse sizes to install to protect the wiring in case of a short.

Wire Gauge for a 1,500-watt Inverter (DC side)

1,500-watt 12-volt inverter

You should use a minimum of 4 AWG wire for 1,500 watt, 12V inverter (DC side) provided the wire length is up to 3 feet long.

This cable size can safely handle the estimated 156 amps of DC current with a reasonable voltage drop when the inverter is loaded up to its maximum capacity.

2 Top Tips to Select the Suitable Wire Gauge for Your Inverter

  • Keep the battery cables as short as possible to keep the voltage drops and power losses at a minimum.
  • To use smaller gauge battery cables, use an inverter/ battery bank combination that uses 24V or higher. The input DC current is significantly reduced ( by 50% from 12V to 24V) while using the less expensive and more flexible DC cables


DC input amps for a 1,500-watt 12 V inverter can be as high as 156 amps from the calculation: DC amps = (inverter output power – 1500 watts)/ (battery voltage – 12V x inverter efficiency – 80%).

DC input amps for a 1,500-watt 24 V inverter can be as high as 78 amps from the calculation: DC amps = (inverter output power – 1500 watts)/ (battery voltage – 24V x inverter efficiency – 80%)

What Size of DC Fuse (amps) for the Inverter?

To protect the battery cables in case of a short circuit, wire a fuse on the positive battery cable always close to the battery terminal as possible.

Consider using a 250 amp DC fuse for a 1,500-watt, 12V inverter to protect the DC battery wires

Wire Gauge for a1,500 watt Inverter (AC side)

You can use 14 AWG or larger for the inverter to appliance cables.

This is rated at about 15 amps and can handle an estimated appliance current of 13 amps from the inverter at maximum power.

You can work out the current draw of the AC side using the formula: inverter power(watts) / inverter AC voltage AC, i.e. 1,500 watts/ 115V, or 13amps.

You may also be interested in this post: What will a 1,500 watt inverter run?

Closing Thoughts

Use a minimum of 4 AWG wire for the battery cables for your 1,500-watt, 12V inverter for up to 3 feet of battery cables.

For longer cable runs, use larger size battery cables to keep voltage drops and power losses low.

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