ok im going to get a RE 12.1 and its going to be wired down to 1ohm 1200rms what size wire do i need i was plannin on 0 or 2 guage and also should the big 3 be the same size or can it be different? thanks for any help
2 gauge will work but there is absolutely no harm if you go with 0 gauge except a little more money to spend. i personally will will use 0 gauge. It will also help if you decide to upgrade at any time. I would also do the big 3 with 0 gauge. NOTE: you MIGHT need to get a H/O alternator.
2awg is kinda harder to find and usually close to the same price as 1/0awg. 1/0awg will also give you some head room to add on later. you can't over do wireing.
for the big three, 4awg is large enough depending on length, but 1/0awg won't hurt there either.
for 1200wrms which is actually underrated, you will need to upgrade the electrical syetem if you haven't already done so.