Your system should have BIG power cables from the batteries to the inverter. The '+' cable here should be fused with a BIG fuse--usually a Class T with a 250 or 500 amp rating. Your inverter probably came with suggested fusing information. If not, try the chart located at: http://www.otherpower.com/otherpower_systems_inverters.html. There are also big circuit breakers you can use for this, but they are extremely expensive. Just the fuse and holder will cost you $60 -- a 500 amp DC breaker goes for $300 and up. You can also run your DC loads through this fuse, though they should have their own smaller load breakers/fuses too.
You should also have fuses on both your DC and AC loads. Your inverter has fuses inside, but it's much better better to blow your breaker first. For the AC side, a standard, inexpensive breaker box will work. But it's made for the 220v feed into your house -- you'll have to bridge the hot side of your 2 vertical rows of breakers with a short piece of #8 wire to make the second row active--otherwise only one row of breakers will have power. Do this where the main feed wires attach to the rows of breakers.
You can also use breakers for the DC side, though standard automotive fuses will work if they are big enough for your loads. Check the specs on the breakers -- only certain kinds are rated for DC use. But we were able to find some at the local Home Depot.
You should also fuse your DC inputs from solar, wind, hydro, etc. This can again be done with a breaker box or fuses.
It's also wise to have a "big switch" on the + side of your system -- rated the same as your big inverter fuse, you can use it to completely shut down everything going in or out of your system. If sparks are still flying when you shut down with the big switch, something fell across your battery terminals! You can also combine your big fuse and big switch in one unit (about $200). This starts to show how handy the use of buss bars can be (see http://www.otherpower.com/otherpower_battery_wiring.html). They give you more places to hook up inputs and outputs, and make it easier to make ALL your + wires go though the big switch......and easier to make all your '-' wires go through your shunt, if you have an amp/hour meter installed.
