I am installing the following amps:

(1) ED NINe.2X
Max Current Draw-85A

(1) Infinity Ref. 7541A
Max Current Draw-85A

**Each Amp is individually protected on each unit with (2) 40A fuses

I plan on running common #4GA from battery to distibution block near amps, then wiring to each individual amp with #8GA.

I would like to use a Breaker at the battery instead of fuse, but would use fuse if necessary.

Should the breaker (or fuse) on main common line be rated at 200A (since I have a total of 170A possible Max Current Draw from both amps)? Next available size down is 150A (which may, or may not be large enough?)

Is it neccessary, or good practice, to use a Fused Distribution Block in the rear by the amps? If so, what should each be rated for assuming 85A Max Current draw?

Sorry if these sound like dumb questions - I'm a Mech Engineer - not Electrical

TIA,
-Jay-

 

The rule of thumb for the main fuse/breaker is add up the fuses on the amps. So you'd have a Max current draw of 160 amps. So the main breaker/fuse should be 160 or a close rating.

You'd more then likely be fine with a 150A breaker since one of the amps is going to be used for full range sound and won't get close to it's max current draw.

You can use either a Fuse or Breaker. Just make sure the breaker is sealed against weather. There are debates in the SPL arena about using breakers and some extreme cars have issues using breaker and are fine with fuses. (It all has to do with the way a breaker "Breaks" off contact.) If you aren't planning on a MAX-EFFORT build, then I wouldn't worry about that.

Remember this: The main fuse/breaker is there to protect the vehicle. It's meant as a safety device to keep the main line from starting a fire in the vehicle.

So with that thinking, fused distro-blocks in the back near each amp, can be for safety if you are worried about the individual lines going to each amp may fail. But really, it's more of a cosmetic look. The lines in the back won't move around easily if the amp is properly mounted and if you don't put stuff in the back that may be around the line.

If you've studied Sinusoidal waves, you realize that Power is a sum of voltage vs amprage increase. Larger waves have more power consumption under the curve do to a slower forming wave and larger amplitude of the wave. That is why amp's running in the sub-freq range tned to draw more current then full range. Also the dynamic draw (large shifts in sound pressure) tend to spike the current draw. Sub-freq (20-120 hz) "Bass" tend to spike current draw more then a Thimbal tap or drum snare or the likes.

 

Thanks for the reply! Not too dumbed down, not too technical.

I can definitely relate a correlation between flow/pressure in a liquid or gas system (something I'm familiar with) to voltage/current in an electrical system. So your last paragraph was not wasted...

 

Cool. Glad to help.