Today I installed the unit using factory supplied cables and installed a 250Amp fuse between the unit and the batteries. I remodeled my electrical box to power my living room (TV, electric chairs, outlets), microwave, center island, and electric meters. There are also sockets for bathrooms, sockets for bedrooms and a TV. I used a 3 wire output and hooked up a 12/2 Romex to an unused 20 amp switch on my RV's panel. I ran it and it works great. Tomorrow I'll lay the 4/0 90c cable from the block to the fuse box to the batteries. I don't trust (2) 5 gauge wire sets. I'm taking a two week trip from Arizona to Florida this Friday. We're planning on going a few days in a row without food ashore so I'll see how it goes and report back. 5 stars so far.