Properly Sized Circuit Breakers & Busbar

[aquajoc730]

Wow. Lots of good info so far. So I figured out the proper wire gauges and fuse loads. I took the advice of maybe using a single fuse block to wire my system and redesigned things. Would you guys mind taking a look at my wiring schematic to see if it looks correct? Thanks and I appreciate all your feedback.

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[Lovetheworld]

When somebody is trying to learn, Its important to follow standardised convention to communicate electrical or other engineering expressions.
Its part of the process. Otherwise a student is handicapped if they try to advance beyond ’paint by numbers’.
Perhaps then stay clear of discussion with electrical professionals. They might not laugh in your face. They may be kind enough to drop a hint worth review to further ones electrical understanding.
Btw,
Both fuses and circuitbreakers are considered devices.

I work with electrical engineers, the ones that design our hardware, and none of them are annoying as you

 

[OllieChristopher]

Wow. Lots of good info so far. So I figured out the proper wire gauges and fuse loads. I took the advice of maybe using a single fuse block to wire my system and redesigned things. Would you guys mind taking a look at my wiring schematic to see if it looks correct? Thanks and I appreciate all your feedback.

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Right on!! looks good!! I don't see why that won't work. I'm assuming you are running a wire directly from battery to DCDC charger and using the circuit breaker as a switch for servicing components. The negative busbar is really the way to go when wiring up stuff. I makes connections much cleaner and reliable. Looking forward to seeing your end result.

When somebody is trying to learn, Its important to follow standardised convention to communicate electrical or other engineering expressions.
Its part of the process. Otherwise a student is handicapped if they try to advance beyond ’paint by numbers’.
Perhaps then stay clear of discussion with electrical professionals. They might not laugh in your face. They may be kind enough to drop a hint worth review to further ones electrical understanding.
Btw,
Both fuses and circuitbreakers are considered devices.

Could you please give it a break? Unless you have something constructive to share then it would probably be best to not draw negative attention to yourself. I don't think Scott Brady had this type of behavior in mind when he founded the forum.

I work with electrical engineers, the ones that design our hardware, and none of them are annoying as you

It's kind of sad that this forum has almost turned into a Bob Is The Oil Guy. There is always someone around who makes it their mission to troll. It's a disservice to members who are here to share and learn.

 

[IdaSHO]

Might not be best practice, or simply un-needed overkill, but for my own wiring I try to match the fuses to the devices they power.
As in, not simply based upon wire size...

For example...If a device typically draws 5amps, Ill wire it for 15 amps, but fuse it for 7amps.

I guess you could argue doing it this way the fuses are still there to protect the wiring, but I would prefer it be more sensitive to problems than less.

 

[OllieChristopher]

Might not be best practice, or simply un-needed overkill, but for my own wiring I try to match the fuses to the devices they power.
As in, not simply based upon wire size...

For example...If a device typically draws 5amps, Ill wire it for 15 amps, but fuse it for 7amps.

I guess you could argue doing it this way the fuses are still there to protect the wiring, but I would prefer it be more sensitive to problems than less.

That's basically about it if the device is not self protected. Can't go wrong with sizing wire a little larger.

 

[PSea]

Total 12V beginner here...

I’m putting together a 12V DC system that includes a 100AH LiFePO4 battery and 1000W inverter. I’ll be using two 100W solar panels and a Renogy DCC30S DC-to-DC charger. Can anyone help me and take a look at the pic to see what size circuit breakers and busbar I should get (circled for reference)? I plan to set up the exact same system. My fridge, lights, and diesel heater will be wired to the fuse box and I’ll use the inverter to charge electronic devices (laptop, phone, iPad, etc.). Any help and advice is appreciated!

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first thing I'd ask is why do you want to use an inverter to charge dc devices? i'd look into a more energy efficient solution rather than going from dc batteries to an ac inverter and back to a dc device. think about it. ;-)

 

[aquajoc730]

Actually, it’s more for things Iike recharging DSLR camera batteries and my iPad, running a few tools, and a small kettle and blender. I can charge most things, like my phone and the kids’ electronics, via USB.


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[DaveInDenver]

Might not be best practice, or simply un-needed overkill, but for my own wiring I try to match the fuses to the devices they power.
As in, not simply based upon wire size...

For example...If a device typically draws 5amps, Ill wire it for 15 amps, but fuse it for 7amps.

I guess you could argue doing it this way the fuses are still there to protect the wiring, but I would prefer it be more sensitive to problems than less.

There's nothing wrong with oversizing wire relative to its fuse (although I'd only suggest documenting it well because trying to figure out a problem in the cabin due to a fuse under the hood might cause someone to pull their hair out). But why not just fuse correctly for a 5A holding (100%) load? Using a 7A fuse to protect a 5A is in that marginal region (140%) where it's not enough to blow quickly (generally 200%) so it might hold an overcurrent for tens of minutes.

 

[IdaSHO]

It was just an oversimplified example.

And depending upon device, and slow vs fast blow fuses, a 5amp device might very well need more fuse anyhow to operate correctly.

 

[llamalander]

The latest diagram looks better, you have the breakers/fuses sized for your max draw, and from that you can pick the size wire to use depending on how far apart components are.
If you are going to skip a fuse on the LiFePo battery, it needs to be within 12" of the fuse hub, but you are much better off using a breaker at the battery to protect the system.
The Blue Sea 150 has its own negative busbar, so you can skip a second one and save yourself some wire.
The solar still has no fuse or disconnect, you need to protect the wires and the people who might be working on those wires, so put in some means of disconnecting the solar.