Wiring Question

[AnthonyO 10+ year member]

Okay I may have miscalculated.
Amps
RF R2-500x1 @ 2ohm
RF R2-300x4 @ 4ohm

from my calculation I should be fine with a single run of 4 gauge. I am running OFC.

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[AnthonyO 10+ year member]

Amp power between the two 800 watts
Both amps are class D, so I am using 80% efficiency or .8
800 divided by .8 = 1000 = p/t
Current => pt/v = 1000/13.8 = 72.5 amps

4 gauge is able to handle 72.5 amps

Correct me if I am wrong

 

[2RZ-FE 10+ year member]

The recommended fuse for each amp is in the manual. The 500x1 is 80 amp and the 300x4 is 60 amp
so use a main fuse of at least 140. A single run of 4 gauge at around 20 feet can handle 150 amps.

 

[shredder2]

Idk why people fuse for their amps, I always fused for the wire size.

4ga I usually fuse 150a

 

[2RZ-FE 10+ year member]

You should fuse for the max current draw of all amps combined. His is 140 a 150 will be close enough. If his max current draw is only 75 amps he would still fuse 4 gauge at 75 not 150. If he decided to step up to 1/0 he would still fuse at 150 not 350.

A single power wire in this case should be 150 near the battery. Then you need a fused d block by the amps. A 60 and 80 amp fuse there going to the appropriate amp. Those are to protect the amps individually since its one run of power wire and those amps have no fuses on them. Amps do have internal protection these days but fuses by the amps can't hurt as long as it's not undersized and being a bottleneck.

You can also run each amp separately to the battery. I do this. One 60 amp and one 80 amp fuse in its own fuse holder. No fused d block by the amps needed since they are powered by it's own line.

 

[AnthonyO 10+ year member]

Yeah I will be running a 150amp fuse under the hood. On my distribution by the amps I will have 80amp for the 500x1 and a 60amp for the 300x4

 

[shredder2]

You should fuse for the max current draw of all amps combined.

Then you need a fused d block by the amps. A 60 and 80 amp fuse there going to the appropriate amp. Those are to protect the amps

Should? Need?... maybe can would be closer to the truth man.

People who fuse for ea amp do so as a personal choice.

I had a 400A underhood and another where the dual runs came up thru the floor in back. Thats it.

Fusing for the wire size where theres a chance of insulation failure due to an accident is all that's needed.

Fusing on a distro block is what some do. I never had/wanted to.

 

[2RZ-FE 10+ year member]

Yours looks fine same size wire. Its when you go from larger wire to smaller wires one would want to fuse.

watch at 13:20

 

[shredder2]

Yours looks fine same size wire. Its when you go from larger wire to smaller wires one would want to fuse.

Wow... you sure got some preconceptions on the needs/whys regarding fusing.

lol... same wire size?

In the system pictured theres 3 amps there and 1 uses dual 1/0 guage, 1 uses 4ga and 1 uses 8ga.

CAF vids are fine man. I fuse for wire size. Not estimated amp draw.,

 

[metalheadjoe 10+ year member]

Idk why people fuse for their amps, I always fused for the wire size.

You must have a brain.