P1000 Fuse block help

[Dordon]

I know this has been discussed many times but my question is I want to add a Blue Sea fuse block to add a few accessories, I will be adding a second battery in the future but for now will run power from the main battery. What gauge battery wires to it and do I need a fuse between the block and battery. Thank you for the help.

 

[Hondasxs]

You did not mention anything about the load you plan to place on the block. That is the deciding factor.

Usually people run 10, 8, or 6.


Sent from my SM-G996U using Tapatalk

 

[Robobrainiac]

This was a good recommendation for me from @bumperm

https://www.pirate4x4.com/attachments/wire_sizing_chart2_titled_filled-jpg.1844330/

Most fuse blocks have a max rating of 100 amps. You will likely not pull more than that with anything you could add to the fuse block system.

Winches should always be directly fed by the battery. No blocks should be used.

Most people don't use anything between the battery and block. If you want something between the battery and block I would use a breaker. A breaker slightly less than the overall rating of the block would guarantee that you would never overload the system.

https://amazon.com/Welugnal-Automot...ing-Waterproof/dp/B0855FP9MX/?tag=sxsweb24-20

 

[bumperm]

This was a good recommendation for me from @bumperm

https://www.pirate4x4.com/attachments/wire_sizing_chart2_titled_filled-jpg.1844330/

Most fuse blocks have a max rating of 100 amps. You will likely not pull more than that with anything you could add to the fuse block system.

Winches should always be directly fed by the battery. No blocks should be used.

Most people don't use anything between the battery and block. If you want something between the battery and block I would use a breaker. A breaker slightly less than the overall rating of the block would guarantee that you would never overload the system.

https://amazon.com/Welugnal-Automot...ing-Waterproof/dp/B0855FP9MX/?tag=sxsweb24-20

Thanks!

My background is in electronics, USN ET-1 (1963 to '70). On ships and airplanes, circuit fuses are first located near the power source and sized to protect system wiring - the idea is that an overcurrent situation due to a short or other overload, will cause the fuse to blow before the wire heats enough to ignite a fire. Fuses are often located on the equipment as well, those fuses are typically much smaller and serve to protect the equipment.

Circuit fuses are sized according to the wire size, ampacity, they are protecting - that would normally be 1.1 to 1.5 times the recommended ampacity. Adding a circuit breaker or large fuse, between battery and fuse distribution block, only protects that short length of wire, as it's size does not allow it to protect the actual distribution system with it's smaller fuses and wiring. That's why it's rarely used . . . just like you normally won't find a CB or fuse between the battery and starter solenoid on a vehicle.

 

[Dordon]

Thank you so much that guide is going to be very helpful

 

[StewB]

What they said above.

I added a 30A marine circuit breaker on 10# positive wire between the battery and fuse box. I largely did it to be able to disconnect the entire box, not really for load protection. Most of your heavy draw accessories will use relays, not heavy current through the box.

 

[bumperm]

What they said above.

I added a 30A marine circuit breaker on 10# positive wire between the battery and fuse box. I largely did it to be able to disconnect the entire box, not really for load protection. Most of your heavy draw accessories will use relays, not heavy current through the box.

Simply using a relay doesn't address concern about protecting distribution wiring. The wire supplying the relay, to then go through the relay contacts to the accessory, should be fused also. This is most often done at the fuse block. The whole idea is to minimize the number of wires attached directly to the battery posts, to the extent possible, protect wiring that, if shorted, could start a fire, and to minimize the extent of power loss in the event there is a short or failure - better to lose one accessory than have the whole thing shut down.

Failsafe is good. This is why on many small aircraft, the positive distribution buss is powered from a relay located near the battery, which is often some distance from the buss (usually for weight distribution concerns). That relay is controlled from the cockpit by switching its negative side. That way it presents no additional risk of fire if the control wire is shorted to ground - it simply keeps things powered on.