18gauge is fine. You can piggy back it off the positive but it's HIGHLY recommended you fuse it. they have generic ATO fuse holders at canadian tire.

 

should i piggy back it at the 4 gauge "in" wire, or on one of the three 8 gauge "out" wires?
how many amps should the fuse be for this wire?

thanks
J

 

at the 4 gauge the fuse is 7.5

 

If following OEM routing and soldering all connector ends it's pointless. Pretty mucha ll big 3 jobs I see have the wires tie-wrapped to the rad support when run like that...it's retarded not to use a fuse on the alt-batt wire

 

^ Fuse at which end? Better put one on each end to be 100% 'safe'. And now you have TWO fuses inline with the charge lead. Most SPL guys view fuses as evil current robbers, so then what's the point of even upgrading the charge lead if you have to put two fuses in it.

See where I'm coming from?

 

from an ultimate SPL goal it's "bad" from no car fire point of view fusing is a necessity.

And both ends should be fused.

 

ok now were fusing both ends???
not needed on both ends just the supply with in 18 inches of source.
the oem alt wire on almost all vehicles is a fusible link which in itself is a fuse. to not fuse an upgrade is just asking for trouble..
but i do understand the spl fuse robbing point!

 

a fuse is just an area of wire with higher resistance. When a certain of current passes through it it begins to heat up. for SPL, anything at all that could lower power to the amps is undesirable.

 

fuse everything, even the RCA wire.

 

LMAO - Nice one YULI