Circuit Breaker Question

[RobbieO]

I'm going to be adding bus bars in the battery compartment, and adding fuse sub-panels to the battery compartment and the helm.
What amperage circuit breaker should I use between the house switch and the bus bar? I'm going to use 4 AWG. And what size circuit breaker at the helm for the fuse panel. The panels are 100a max I believe. Thanks.

 

[Beachbummer]

If the run is short enough you could go to 100amps according to this chart,

Automotive Wire Amperage Capacity Chart - Jasco Automotive Ltd

AUTOMOTIVE Wire Amperage Capacity Chart Recommended Length and Amperage for Automotive Wire while maintaining a 2% or less voltage drop at 12 volts Automotive Wire Size 5 Amps 10 Amps 15 Amps 20 Amps 25 Amps 30 Amps 20 Gauge Wire (AWG) 4.5 ft 2.2 ft 1.6 ft . 18 Gauge Wire (AWG) 7.3 ft […]

jascoautomotive.com

The lower the number the better for circuit protection. (but of course it limits your capacity. )Depending on your future plans for this bar I would select the lowest reasonable number that works.

 

[RobbieO]

If the run is short enough you could go to 100amps according to this chart,

Automotive Wire Amperage Capacity Chart - Jasco Automotive Ltd

AUTOMOTIVE Wire Amperage Capacity Chart Recommended Length and Amperage for Automotive Wire while maintaining a 2% or less voltage drop at 12 volts Automotive Wire Size 5 Amps 10 Amps 15 Amps 20 Amps 25 Amps 30 Amps 20 Gauge Wire (AWG) 4.5 ft 2.2 ft 1.6 ft . 18 Gauge Wire (AWG) 7.3 ft […]

jascoautomotive.com

The lower the number the better for circuit protection. (but of course it limits your capacity. )Depending on your future plans for this bar I would select the lowest reasonable number that works.

If the run is short enough you could go to 100amps according to this chart,

Automotive Wire Amperage Capacity Chart - Jasco Automotive Ltd

AUTOMOTIVE Wire Amperage Capacity Chart Recommended Length and Amperage for Automotive Wire while maintaining a 2% or less voltage drop at 12 volts Automotive Wire Size 5 Amps 10 Amps 15 Amps 20 Amps 25 Amps 30 Amps 20 Gauge Wire (AWG) 4.5 ft 2.2 ft 1.6 ft . 18 Gauge Wire (AWG) 7.3 ft […]

jascoautomotive.com

The lower the number the better for circuit protection. (but of course it limits your capacity. )Depending on your future plans for this bar I would select the lowest reasonable number that works.

Thank you for the great info. I plan on running 4AWG to the helm to a fuse sub-panel rated @100a. So maybe go with a 65a breaker there. I have 2-100a, and 2-65a on hand. Thje bus bars can handle 150a, so maybe the 100a there. I don't plan on adding high amperage loads. If I add an amp, I'll put it by the batteries since I have the bus bars there. Just trying to think ahead.

 

[Beachbummer]

I'd suggest if you want to use the 100amp switch just see what you can do within reason to keep the cable run as short as possible.

 

[HangOutdoors]

All depends on what you plan on running at the helm. I did a 65amp to the helm and then I did 100amps between batteries and switch.

Add up potntial draw

 

[RobbieO]

All depends on what you plan on running at the helm. I did a 65amp to the helm and then I did 100amps between batteries and switch.

Add up potntial draw

Perfect.....Probably lights, USB ports, fume detector, stuff like that. No amp..