10 Gauge wire enough for my amp 400 Watts RMS
08-02-2009, 01:02 PM
#21
50 Watt CAFz'r
Join Date: May 2007
Posts: 384
Not a fire hazard... It's simple science...
10awg wire is rated for 40 amps continuously. A 400 watt amp (Considering a sign wave @ full rated power)
Lets say for fun @ a 12V average voltage: 400/12 = 33.33A Or, when his car is charging: 400/14.4 = 27.77A
That looks pretty good to me, and that is even assuming full rated power 100% of the time which will never happen.
The only way a fire could start is if there is a short directly to ground with no fuse inline. But if you want to talk about that, larger gauge cable is more dangerous than small because it can carry more short circuit current. Thus, bigger sparks, bigger arc, etc, etc. Given this, if a fuse fused as you said previously which I take as meaning "failed to blow", the danger of fire would be worse with larger wire. Besides, fuses "fusing"??? I think you mean circuit breakers "fusing", but most people don't use CB's in their systems...
I mean, its a car anyway. This is the same logic behind the wires running through the wooden studs of your house. Yep, where your family and countless millions of others sleep every night... But we don't question the sizing in that case. Would you insist your contractor run 10awg wire instead of 14awg in your walls on every 15A breaker???
Lyle
10awg wire is rated for 40 amps continuously. A 400 watt amp (Considering a sign wave @ full rated power)
Lets say for fun @ a 12V average voltage: 400/12 = 33.33A Or, when his car is charging: 400/14.4 = 27.77A
That looks pretty good to me, and that is even assuming full rated power 100% of the time which will never happen.
The only way a fire could start is if there is a short directly to ground with no fuse inline. But if you want to talk about that, larger gauge cable is more dangerous than small because it can carry more short circuit current. Thus, bigger sparks, bigger arc, etc, etc. Given this, if a fuse fused as you said previously which I take as meaning "failed to blow", the danger of fire would be worse with larger wire. Besides, fuses "fusing"??? I think you mean circuit breakers "fusing", but most people don't use CB's in their systems...
I mean, its a car anyway. This is the same logic behind the wires running through the wooden studs of your house. Yep, where your family and countless millions of others sleep every night... But we don't question the sizing in that case. Would you insist your contractor run 10awg wire instead of 14awg in your walls on every 15A breaker???
Lyle
Last edited by godzilla1978; 08-02-2009 at 01:04 PM.
08-03-2009, 06:09 PM
#23
50 Watt CAFz'r
Join Date: Jun 2008
Posts: 103
QUOTE=godzilla1978;503118]I said it could happen with a worst case senario.It's a long shot at best,but can still happen.I didn't say it WILL happen or that there is imminent danger, just that it's something to keep in mind just in case.There's also the lenth of the wire to take into account the longer the wire = less current carrying capability. With your equations your also assuming that your amplifier is operating at 100% efficiency, which will also never occur most A/B class amplifiers operate at about 50% efficiency, mono blocks at about 75%(I'm rounding off to keep it simple) less efficiency=more current to make the same power because the voltage is pretty much constant. So with even your conservitive numbers the current draw would be much higher. As for the house wire there is way less current in house wiring than in a car. Car = 12-15v@40-180amps vs in a house 120v @1-5amps. Current is really what were worried about here because the more current there is more electrical potential which also means more heat. Where also assuming that he is using true 10ga. wire and not some cheap knock off thats really 12 or 14 guage wire. To much assuming for me.[/QUOTE]
Okay killer...
You're probably right...
In the worst case senario, if the wire is twice as small as it was sold as, and the amps rated output is over the factory specs, and the amp is infact class A/B continuosly playing a sign wave @ max output, and the inline fuse doesn't blow first, and the amp doesn't burn out first, the wire could get hot enough to start a fire...
I guess I never thought of it that way...
Lyle
Okay killer...
You're probably right...
In the worst case senario, if the wire is twice as small as it was sold as, and the amps rated output is over the factory specs, and the amp is infact class A/B continuosly playing a sign wave @ max output, and the inline fuse doesn't blow first, and the amp doesn't burn out first, the wire could get hot enough to start a fire...
I guess I never thought of it that way...
Lyle
Last edited by Lyle's GTP; 08-03-2009 at 06:11 PM.
08-03-2009, 07:50 PM
#25
50 Watt CAFz'r
Join Date: Jun 2008
Posts: 103
I guess if your electrician bought everything out of the back of a truck, and the government certified current ratings of all your appliances are grossly underrated, than yes, it's possible.
I didn't even meet my electrician, I'm probably screwed...
Lyle
I didn't even meet my electrician, I'm probably screwed...
Lyle
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