Yes, but we are also talking about someone asking for a 500w amp, and no offence to the OP but i doubt that it is RMS power we are talking about.



Why? You know that any cable can run any voltage/current, the only problem is heat and voltage drop across the cable that is the problem... 110 amps? x 12 v (which in reality might be 13.5) gives 1320/1485 watts which is over double what i think you need. Safer to be oversized? Well what if there is a little short somewhere that the fuse doesn't blow from? its best to be oversized to a point, but dont go too far over what you need.

Look if you have seen an 800 watt kit for cheap (how much we talking here) then get that, it will be more than enough.

yeah i know probably not rms wattage but its a cheapie for now so i can run my sub and fronts till i can afford better but thanks for all the help guys much appretiated

H=I^2.R

So yes... If you run 8awg cable to its limit (50amps) then you are producing a fair bit heat in the cable... The cable temp increases so does the resistance and hence the temperature further... like you said you get a point where the resistance of the wire is great enough to give a voltage drop of a significant value to hinder the amps performance and sometimes in a big way (I do a bit of stage audio and am more familiar with it than big car audio, but I imagine the same principals apply)... Jaycar's measurements put 8awg at 7.5mm^2 and 4awg at 21mm^2 so close to 3 times the effective area... So therefore you double the cables effective area and with this formula:

R = (pl)/(A) (rho times length divided by area)

that if you double its area you'll get half the resistance and hence a half of the heat lost this will reduce the resistance increase when "hot" and hence less voltage drop and maintain a much healthier amplification and sound quality...

Like you said though... Each to their own and don't go completely nuts as then the cost doesn't outweigh the benefit... But its not worth running a cable to its limit...

If you have a little short you risk fire, no matter what the circumstances... Its like that with household wiring and car wiring... If a fuse doesn't operated then you risk trouble... You hope, the current loss is to a point big enough when the cable starts to weld and transfers enough current to blow the fuse before getting hot enough to start a fire... Either way not a good situation... Always best to grommet/gland any and all sharp edges... Prevention is the best method, not the circuit protection...

I do disagree with one thing, as a substation technician I disagree with any cable carrying any voltage and current... I would hate to see you regular old household cables (rated nominally to 1kv) carry our 11,22,33,66,132,330kv voltages used in distribution of power, this determines how thick and the type of insulation for the cable, if exceed you risk break down of insulation and tracking... and Current capacity determines the cable area, if exceeded you risk insulation ignition due to heat and cable degradation or melting if enough current is feed into it... Hence why spark plug leads are a tiny wire in a mass of insulation... bugger all current, massive voltage...

think I've rambled enough for now

+1 to anyone that is new, always use a grommet as you said, 50c + 5 mins work is not worth loosing your car over.


Should have expanded what i said, as long as the shielding is thick enough and you have a way to keep the cable cool enough it can be done, is it sensible? Not really


im sure someone learnt a lot though haha.


You can put a 60 amp fuse on them with no troubles. But how often will it reach 50/60 amps? Not very often.

alright now for the straight answers HOW THICK? (8G 4G) HOW MANY AMPS THE FUSE NEEDS TO BE? (30 40 50 60)

The 800w kit you saw should be fine. Since your amp is probably only 50w a channel 8guage should be fine.

Yeah I agree... I good guestimate is the fuse size in the amp... If its a 30amp fuse the amp will not draw much more power... If it does it will blow that fuse... So as an electrician my instinct with regards to discrimination is to run wire that will continually handle that rate current of that fuse (remembering it takes more than 30 amps to pop a 30 amp fuse...)

So If its 30amps, I'd run 8awg cable, and put a slightly larger fuse upstream (called discrimination) so a 40 if nothing else uses this power circuit... if you run a cigarette lighter socket in your boot off the same power wire, well a cigarette lighter socket is rated in some instances up to 10amps (120Watts) so the cable fuses would be a most likely a 50amp fuse if I were doing it...

so i will buy 8G and put a 40 amp

I haven't read the whole thread so I apologise if any of this has been said.

8GA should be fine but I would still run 4GA if you can for peace of mind.

I have a 4 x 130w rms amp mounted to the backseat of my EB. Installed in March 2006 and hasn't missed a beat. Puts out a great sound through the boston acoustic splits I have up front too.

i am running a jaycar response dvd head unit and 7'' flipout screen,6.5 kevlar/carbon fibre splits,1 farad jaycar capacitor and a 800w monoblock amp powering a jaycar carbon fibre dvc sub,i am also running gold terminals and cabling from jaycar.this gear would have to be best bang for your buck.my system is crisp,clean and loud and i love it.

rear i am running response prescision 6 1/2 kevlar splits ,prescision cross overs and tweeters aswell as ribbon tweeters keeps up with 2 1000w dvc subs great.
imo response is the best value for money i.c.e
in fact im considering changing the front titanium splits to response at around half the price with better cross overs

I run a set of the 6.5" kevlar splits in my 4wd, they work fine, not as good as the speakers in my Xr6 but they are 8" 3way Dyn's so I would expect not....

Jaycar is without a doubt a favourite shop with most of us. Their amps are awesome, even value for mone, but up there with ones twice their price, im sure many would agree. The response series speakers are good, but sadly not all that. Better than stock but after trying a few id say spend just a few more dollars and try to hit the sales etc.. and get something with a decent name and reputation. Not that i like, or would buy fusion (green series) as seen with mates cars, but i believe they are at the low end of upgrades along with response. Nothing comes cheap but if you shop around im sure you can come across better for the money. Best bet is to listen to others advice or better crank them up on the shop walls to see the difference. Still stick by Jaycar being awesome though.

Jaycar is without a doubt a favourite shop with most of us. Their amps are awesome, even value for mone, but up there with ones twice their price, im sure many would agree. The response series speakers are good, but sadly not all that. Better than stock but after trying a few id say spend just a few more dollars and try to hit the sales etc.. and get something with a decent name and reputation. Not that i like, or would buy fusion (green series) as seen with mates cars, but i believe they are at the low end of upgrades along with response. Nothing comes cheap but if you shop around im sure you can come across better for the money. Best bet is to listen to others advice or better crank them up on the shop walls to see the difference. Still stick by Jaycar being awesome though.