Inverter installation

[PaulRainbow]

Thanks, but a bit confused. Why changing shunt fuse to 350A would not be a way to go? Isn't a shunt fuse = battery fuse? Or non fused 1-1.5m cable from battery to shunt is potencially problematic?

Any picture of cable covers and how to properly cover terminals would be great.

Regarding 1.5mm² and 2.5mm² cables that connect to the switches. The red one is for Digital AC 1x6A and it seems does not need to be fused (check picture). Grey/brown is for switch panel voltage indicator.

Spoiler: Digital AC 1x6A

View attachment 83942

The fuse in the shunt only protects the cables after the shunt, the cables between the batteries and shunt have no protection, considering the close proximity of the shunt itself to the engine, i'd put a fuse at the battery, this (if it's a 350a fuse) will protect the cables from the battery to the shunt and from the shunt to the inverter, so no need for additional fuses in the 2x 50mm cables and no need to change the fuse in the shunt.

As soon as you step down in cable size, those cables need to be fitted with suitably rated fuses. I can see at least four wires connected to the isolator switches and none of them are fused. Fuses are fitted to protect the wiring and in some cases the equipment too. In the case of the Digital AC that you show about, it shouldn't have DC connections, those two red wires connected centrally should be an AC supply and load, the oblong device with the vertical line, fitted to the cable marked "L" is a fuse. It's a bit odd if you say this is connected to the DC isolators.

The simple answers are, fit a fuse at the battery, that protects the entire run of 2x50mm cabling. At any point where the cable drop in size, you should fit a fuse rated for the cables, no matter if the equipment installation instructions say so or not. Don't forget, the negative cables will also need to be 2x50mm cables too.

 

[Kemp]

I can see at least four wires connected to the isolator switches and none of them are fused.

Top 3 switches are: engine, house, bow thruster. Probably you are talking about 4 wires connected to house switch: two 35 mm² are connected to separate 80A Blue Sea Systems Bussman Series 187 MRCBs and smaller two go to two switch panels. Probably time to make a proper wiring diagram...

 

[PaulRainbow]

Top 3 switches are: engine, house, bow thruster. Probably you are talking about 4 wires connected to house switch: two 35 mm² are connected to separate 80A Blue Sea Systems Bussman Series 187 MRCBs and smaller two go to two switch panels. Probably time to make a proper wiring diagram...

If you fuse the 2x50mm cables as i said, those cables will be safely protected.

If you connect a cable to that circuit that is smaller then 50mm, it will not be protected, if it shorts it will burn out, possibly starting a fire, before the 350a fuse blows. So, if you connected a 10mm cable to the domestic isolator, to supply domestic switch/fuse panels etc, you would need to fit a fuse, close to the isolator, rated at no more then 75a. If you connect a 2.5mm wire it needs a fuse no greater than 30a, etc etc.

Your 35mm cables are rated at 240a, so are well protected by 80a fuses (note though, there is no protection between the isolator and the fuse, so i hope it isn't too far from the isolator). But, the wires that look to be 1.5mm and 2.5mm do not appear to be fused.

All circuits need to be protected at the supply end, there is no need, or any point, in fitting fuses at the load end of a wire.

 

[Kemp]

Not sure but it seems you are not taking into account DC distribution with fuses.

It has 4 connections: 1) alternator with 125A fuse 2) hydrogenerator with 80A fuse 3) charger with 80A fuse and 4) house isolator switch with 125A fuse.

I will work on wiring diagram to connect all dots and post it in a few days.