Hooking up a DC TO AC inverter

Hi could anyone help me to properly hook up an inverter. Why I ask I had one hooked up in a box truck I bought and it allmost burnt up my truck.
I believe it was due to a high resistence connection to the battery side. It hade no curcit breaker set up and I believe if it had it would have not caught the back of the truck on fire.
I checked the inverter out after removing it from the truck and it works fine.
Please if someone could advise on proper hook up I would be thankfull.

Many Thanks
Charles Barto