Wire gauge question

okay, this is a pretty unorthodox question. i want to hook up an amp in my trunk...it consumes a max current of 30A. i already have a 4-gauge wire running from my batt to under the passenger seat to power another amp that consumes 30A max. running another 8-gauge cable from the passenger seat (via a distribution block) to the trunk on my particular car is a major PITA. BUT, the factory harness that runs from the dash to the trunk has 11 UNUSED wires, between 18 and 14-gauge. these are for thinks like humidity sensors, abs sensors, etc, that my rather base model does not have. i know this from my electrical schematics, and i have verified this with my multimeter. here's my whacky question: can i splice these 11 wires in parallel to achieve something close to an 8-gauge wire? another way of putting it is, how many 16-gauge wires does it take to equal an 8-gauge wire? is there any problem with the fact that not all the strands of the different wires are not in contact with each other? is this completely whacky?

Not really whacky, as there is a cumulative effect of current over multiple strands of cable. If it is coming from the same source, and terminating at the same destination, you can sum the capabilities to arrive at a known current capacity. The break down of current (assuming multistranded, shealthed [not free air] cabling) 8...39A 10..31A 12..23A 14..17A 16..13A 18..10A 20..7.5A 22..5A Good answer? DXAV

thanks. it makes sense that there is a cumulative effect of bundling cables, but your breakdown seems a bit off... if a 22AWG wire is capable of handling 5A of current over a certain distance, then in theory i would need to bundle ONLY 8 separate 22AWG wires to achieve the same current capacity as a single 8AWG. that seems hard to believe.... that 8x22AWG cables could carry the same current as efficiently as 1x8AWG. can anyone else concur? i guess it would help if i knew the literal definition of AWG, as opposed to just knowing that lower number = thicker wire = higher current handling. i should read up on this more....

okay, i did a little research and came up with this nice chart: http://www.alphawire.com/PAGES/379.CFM i did a VERY informal analysis, and compared 22AWG wire to 14AWG wire. 14AWG wire is about 6x heavier per unit length as 22AWG. the resistance in ohms of the 22AWG wire is also about 6x more than 14AWG over the same length. therefore there is a near linearity between cross-section area of a wire and it's resistance. SO, if it takes 6 22AWG wires to equal the capacity of 1 14AWG wire, there is no way that 8 22 AWG wires can equal 1 8AWG wire (the chart would list AWG smaller than 14 so i couldn't do a correct comparison). does this make sense?

I was using my EE electrical handbook from last year. south is right about the resistance, though. As the guage increases, so does the resistance. But from recent RADAR designs I have done, combining multiple 22 AWG wires to cumulatively reach 7.5 amps has worked in our system for months now. Just working from what I know.....I could be wrong (happens all the time!) BTW: AWG - American Wire Guage DXAV