wire size

[dspiveysr]

That is correct, if you use wire with a current capacity less than circuit current the wire will overheat you will also experience excessive voltage drop.
Wire should be sized according to the maximum anticipated load and fused accordingly, fuses are not there to protect the equipment at the end of the wire, they are there to protect the wire.

[rickst29]

Originally Posted by Kidkraz

I am not great when it comes to electrical issues, but am I wrong in thinking. That if you used a smaller gauge wire it could overheat when trying to power an item that its not rated to power properly?

It will overheat the insulation (risking fire) AND also cause "voltage drop" between the batteries and the Inverter.

Good "12 volt DC to 120 Volt AC inverters" will shut down to protect themselves from excess "voltage drop" typicalty quitting at about 11.8 volts. But the 'voltage drop' which may occur in starting a compressor, or running an unfriendly microwave, can occur "to quickly" for the Inverter to protect itself that way.

There might also be a question about drawing high power (amps) from the batteries themselves: Regular auto and truck batteries are built for short periods of very high current (in starting the car), but "deep cycle" batteries used in trailers are built for longer use at lower current levels, and may not be capable or extreme current levels.

[Wavery]

Originally Posted by barnyard

have 1000 watt inverter mainly to power 110v refridge. plan on mounting close to battery( 3feet) what gage cable from inverter to battery?

If you don't mind me asking, what inverter are you using?