Correct size fuse for 12V circuits

[FLYNCLD]

I am installing a new power distribution panel in my 62' Flying Cloud. As there was no panel there before, and it appears all the 12v loads were essentially on one circuit, I will be dividing up the load into multiple circuits. My question is, is there a simple way to determine what size fuse you should use for each circuit. I am using 12G wire and it is my understanding that the fuse is there to protect the wire, not the devices, but there must be some correlation between the load/wire/fuse? Any help out there for use non-rocket scientists?

Thanks!

FLYNCLD

[uwe]

Depending on how many wires you need to fuse and how many users are on the circuit, I would start with a 15 or 20A fuse for a 12G wire. Much also depends on the wire length.
You should use much heavier wire from the battery or converter to the fuse panel, though, like a 4g battery cable.

[HowieE]

#12 automotive wire is generally fused at 20 amps. # 14 wire at 15 amps.

Just make sure you fuse for the SMALLEST wire size in the circuit. Generally the factor would use the same size wire throughout a circuit but if anyone else added something they may have down sized that wire. Just check to be safe.

[FLYNCLD]

That pretty well confirms what I have been thinking. As always, thanks to the members. The Forum ROCKS!!


FLYNCLD

[Lumatic]

On early 70s the main power fuses connecting the converter and battery to the fuse panel were 40 amps. There were 4 other 20 amp circuits for the operational trailer circuits.

[87MH]

Originally Posted by FLYNCLD

... I will be dividing up the load into multiple circuits...there must be some correlation between the load/wire/fuse? Any help out there for use non-rocket scientists?

A fairly decent footage/gauge/amperage spreadsheet can be found here:

Voltage drop, distcance and wire guage

Use stranded copper hands down - the finer the strands the easier it will be to work with - solder all of the end connections if you can.

Don't scrimp on the wire gauge - the difference in the price of wire just does not justify cutting any corners - when the trailer is finished you will be glad that you "overwired".

Grounding is always a problem on older trailers - best to strap to both the frame AND the shell - better yet - run grounding wires from a central ground buss to each end user of the 12 volt system.

Read my signature line - do it right the first time....

[Shiny metal]

I have a used 06 Safari and have no reference material. I would like to pick up some spare fuses. I would also prefer that I not remove the existing fuses from the fuse panel to use as an example. Can anyone tell me the length and amprege of the fuses I need to keep on hand. Thanking you in advance.

[HowieE]

Have you taken a look? I think they are circuit breakers not fuses.