Fusing my distro blocks..

[danteBirosel 5,000+ posts]

My distro blocks are 1 gauge in and 4 gauge out and are not fused. Do i need to fuse em? What are the advantages and disadvantages?

Btw, the fuse right by the battery is 140A ANL

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[dru 10+ year member]

i want to know this too

 

[helotaxi 5,000+ posts]

You should fuse to the current capacity of the smallest wire. In your case the underhood fuse is the right size for the 4ga (good to 150A) so unless your amps lack internal fusing, you should be good.

If, however, you had, say, a 250A fuse under the hood, you would need to fuse the 4ga either at the distro block (fused distribution block) or immediately thereafter with a fuse block or individual fuse holders for each wire.

 

[n2audio 5,000+ posts]

What are the advantages and disadvantages?

To add to what helotaxi said...

The point is with larger wire up front you'd typically have a much larger fuse - Let's say 250A for example --

It's possible (unlikely, but possible) that the smaller wire coming out of the d-block could be shorted, but it may not be pulling enough current to blow the 250A fuse, at least not immediately, and could get hot enough to be dangerous.

With the appropriate sized fuse in the block - if that smaller wire touches ground the fuse at the block would blow very quickly.

Since you have a 4 ga sized fuse up front it should be sufficient to protect the smaller wires.