I have a new-to-me 1988 Formula 311 SR-1 that has been essentially completely redone/maintained/re-engined/etc... The previous owner used it on lakes and seems to not have even tried to use the shore power set-up. I plugged it in and got no lights, etc...so I opened the panel. As you can see in the picture, I found the main fuses all missing. I am trying to figure out what fuses go in the four locations AND how to safely (without starting an electrical fire or blowing out other fuses and circuit breakers) check to see if the bos works as advertised. My initial assumption is that the fuses were removed during rework and were just replaced...but if they were removed "for a reason" I don't want to find out what that reason was the hard way.
Thanks,
Tom

Looks to me like the panel was never connected to anything, as there aren't any wires connected to the individual circuits. Fuse size is mostly determined by connected wire gauge. After helping my brother with a wiring problem on a boat he bought, I won't turn anything on until I trace the wiring myself. His 120VAC circuits were all wired wrong and would have toasted his boat had he started his generator. Could be they are just using the inverter to charge the batteries?

Thanks, I will investigate more!

Is that a old school inverter? The fuses are clearly 12V. The circuit breakers are 110V. If you pull the lower panel it may reveal more...........

You have opened the 12 volt side of the panel. Agree that it looks like it wasn't used.
Agree the 110 volt side is in the bottom. And those breakers look like they are in the off position.

They are off...I found them that way and flipping them on did not illuminate the LED, so my inspection got deeper and I stopped when I fuses missing. I will investigate further. For now, I will just keep a trickle charger/battery tender in the boat to keep the batteries fresh.

Where are you located? Never mind, I just saw yo post in the next topic. Friend of mine has a new to him 357. His shore power was all jacked up, took it to Burgers in Lake Ozark. In and out in 60 mins. All good now.

Roger that. As you probably discovered, I am near Pensacola, Fl. (western panhandle). Anyway, I will slowly "wring it out"...I KNOW electrical engineering (as I had to take it twice as a mechanical engineering student).
Tom

So, it looks like the lower part of the unit has wires attached and the upper part shows 12+ Volts DC across the red/black contacts when the Perko switch is on and 0 V DC with Perko off. Any suggestions for the next safe troubleshooting step?

See pictures...does it look like I just need to install fuses? What size (fuses)?