power and ground wiring configuration for two amps

[cjmiller]

Adding two amps for speakers and sub, amps to be installed under glove box. Amps require 4 ga wiring. Wondering what the best wiring option is:

1. 0 ga wire off of the perko run that to the location of the amps (approx. 16' run) and then split it to the two 4 ga wires.
2. 0 ga wire off of the perko for 4' and split off the two 4 ga wires to run the rest of the way
3. Connect both 4 ga wires to the perko and run them seperately to the amps

If I go the 0 ga route would the fuse be installed on that line or should each 4 ga line have it's own fuse?

I have read about every stereo upgrade post but this type of information is usually lacking.

[xlint89]

What size amplifiers are you installing? How many amperes are they going to be using? (what size fuse does each amp require)

Is your 16' length including the ground wire? (Elec needs to run back to the battery, so 16' of positive wire is equal to a 32' run for electricity)

Knowing those and using this chart will help determine the best route for you.

https://www.westmarine.com/WestAdvisor/ ... d-Ampacity

[cjmiller]

thanks, I did figure out what size wire I needed to run. I was trying to figure out if running a large wire and splitting it near the amps was better than running two individual wires to each amp, keeping them independently powered and grounded?

[xlint89]

I can help you better if you answer the questions.

[cjmiller]

1,400 W max power rating, class D, will be used to run 4 ohm speakers at 125 W RMS x 4 channels. Amp has (2) 30 A fuses. Total run from battery positive to amp and back to battery ground will be around 32' long. Also want to tie the head unit ground into the batteries as well to avoid any interference issues.

Any recommendations on wiring configurations and inline fuse sizing is appreciated.

[bruceb58]

You fuse for the smallest wire. Any reason why you think you really need that large of a wire for amps? What size are the amps and what is the current draw?

[xlint89]

I thought you were looking to run multiple amplifiers?

One amp drawing max. 60 amperes. So your 4 AWG wire from the battery switch to the amplifier is fine.

Place an inline fuse or breaker for 60 amps as close to the battery as possible. (reason being if you ever trip or pop a fuse, the power wire leading up to that fuse/breaker is still live and potentially dangerous. That's why you want it as close to battery as possible)

[cjmiller]

I am running two amps, both are the same amp. I assume that the 10% drop table from West Marine is appropriate for an amp? My options are to run separate 4 AWG wires for each amp or run a single 2 AWG power and ground to the amp location and split it there. Any advantages to either option?

[bruceb58]

What is the power draw of the amp?

[xlint89]

Ok, sorry I misread your post. I thought you wrote (1) 400 watt amp. You actually wrote 1,400 watt amp.

No one uses max wattage for amplifier reference. What amps are you actually looking to install? Brand and model

Bruce, in his above post he says the amplifier has 2 x 30 amp fuses. So max amperage is 60 per amplifier.

[bruceb58]

Bruce, in his above post he says the amplifier has 2 x 30 amp fuses. So max amperage is 60 per amplifier.

That is the max current where the fuse will blow. For wire sizing, you need the max current that the amp operates at.

If the Amp was really a 1,400W amp, @12V that would be 116A. I guess eventually, we will find out the real numbers. He also says 125Wx4 which would equal 500W. That would be 40A. 16' of 4 AWG(32' round trip) would drop 2.65% of 12V @ 40A so 4AWG would be WAY more than sufficient. 6AWG would drop 4.2% and 8AWG would drop 6.7%. 8 AWG would be more than sufficient. So called audiofiles somehow come up with these strange ass ideas that you need to go way overboard on wire size.

[cjmiller]

thanks for the input so far, I am running two (2) class D (4) channel amps to power (6) speakers and (1) sub. Each amp is rated at max of 1400W, which is meaningless. I will be running one amp at 125Wx4 RMS and the other amp at 125Wx2 and bridging two channels to get 350Wx1. I am planning on running a single power and ground from the battery to the location of the head unit, where the amps will be installed. I have read that this reduces distortion over running each amp seperately. The total run there and back is approx. 32'. I realize that even at 500W and 600W RMS I will rarely, if ever, actually run the amps at that power level.

That is what I am looking for input on, what current draw should I be using to size the wires? My current thought is 2 AWG wire with a 150A fuse from battery to amps, splitting it to each amp with 4 AWG wire. If that is complete overkill and I could run a single 4 AWG wire and split it at the amps to 4 AWG to each amp that would save a lot of $$.

[bruceb58]

Read my previous post. 8 AWG to each amp would be fine. Use a 50A fuse/breaker on each wire run from the battery.

[cjmiller]

thanks Bruce

[xlint89]

CJ, I'd s till like to know what amplifiers you're actually using.

Bruce, I like to overbuild my stuff for possible expansion later on. There's not much of a problem going oversized on power wire, other than added cost and weight.