No, it will not. Use the wire tables from the National Electrical Code or find a copy of "Ugly's" at your local big-box store in the electrical section. Generally, 12 awg is OK for up to 20 amps, 10 awg for up to 30 amps. It takes a lot of Ohms law work to otherwise figure it out. Since it's a 12v system, I'm assuming that you're installing an obnoxous power amp in your vehicle. The run isn't that long, so the expense won't be that great. Go for the 10 gauge stranded wire. You can get it at the automotive store in short lengths or at the big box store in longer lengths. An electrical jobber can run you off some specific lengths so you won't have to pay for a 100-foot roll when all you need is 12 feet. The jobber can supply it in white, black, red and green at a minimum and may be able to come up with other colors to boot. For power in a car, I'd stick to black (negative) and red (positive).
thanks guys, From the link Eric I looked at chassis wiring (30A) and it said that was a conservative rating lol so I thought it would be ok.
Thinking about it now, the amp used to be driving two 12" speakers and it would sometimes pop a 20 amp fuse if you were driving it hard that's where I got the power rating from. However now I will only be driving one 12" speaker, so I might have been a bit generous to think it will pull 20A now?
Not sure how you blew the 20 amp fuse but the way I look at it is that if you had 2 4 ohm speakers running off 12 volts the peak current would be 12/2 or 6 amps. Even if it's a bridged amplifier you could only get 12 amps peak. So I think your wire size is ok for 1 speaker but your earplugs may be to small.
High power car amplifiers use a switched-mode power supply that boosts the 12V to plus and minus much higher voltages to drive a sub-woofer with hundreds of Watts. 30A from 12V is common.
The wire size in the table accounts for a few volts of drop which is fine for home wiring with its much higher voltage but it is bad for a supply of only 12V.
Use much thicker wire for a lower voltage drop.
The wife's amp uses AWG 6 straight from the battery and is fused at 50 Amps. I believe her main amp is like 300 watts or so. Now that I think about it I should rip that system out as we are dumping the Jeep. She has a new truck with a Bose system.
Danrogers, do you know the actual amp ratings? I would do as AG and others suggest or there will be I*R losses. Overkill it!
Blimey 50A! I'm not sure on the exact power output of the amp, I have not got it with me at the moment but I think the print has worn off the front too as its pretty old.
I think I'll look at going up too 10 awg or something, its just that I have a reel of 14awg that I was hoping to be able to use but I won't bother now
Blimey 50A! I'm not sure on the exact power output of the amp, I have not got it with me at the moment but I think the print has worn off the front too as its pretty old.
I think I'll look at going up too 10 awg or something, its just that I have a reel of 14awg that I was hoping to be able to use but I won't bother now
A run of 10 feet (20 feet round trip for positive and ground) of 14 AWG will have a drop of about 1.03V for 20A of current. So you can calculate the effect of paralleling wires or different distance from that.
The voltage drop will be reduced by the number of parallel wires (e.g. 3 parallel wires will reduce the drop to 1/3 that of one).
The voltage drop is also directly proportional to distance.