General Different gauge wiring to subwoofer

[W Bakker]

Hi all,

I just purchased a jbl basspro nano subwoofer. The subwoofer was sold in a kit with a 8awg power cable but the jbl wiring harness uses 14awg cables. What is the safest way to connect these together?

Battery - 8awg cables - included 60 amp fuse

60 amp fuse - 8awg cable - through firewall into cabin

8awg cable - ??? - 14awg cable with 15 amp fuse included with subwoofer - connect to subwoofer under driver seat.

Thanks in advance!

 

[Ralf S.]

8AWG wire is rated for either 40 amps (3 core) or 35 amps (4 core) at 60 degrees... and is typically protected by a 15 amp fuse.

I have no idea why the kit came with a 60 amp fuse.. (if that's what you mean?) that's way in excess of the cable's capacity.


Ralf S.

 

[John202020]

Sounds about right to me, it's not unusual to use this cable for up to 60A remembering it's not a continuous load, my 360w rms system with two amps used this cable with a 50a fuse, run the cable right to the amp assuming built in fuse

 

[W Bakker]

Hi everyone,


I ended up installing the 60-amp fuse under the bonnet, near the battery. From there, I ran the 8AWG cable through the firewall and added a 15-amp fuse in a fuse holder, connected using nylon cable lugs. I’ve attached a rough wiring diagram along with some photos of the setup below.

I also decided to replace the door speakers with a pair of JBL CLUB 622s, as the original ones began rattling whenever the volume was set above level 8. You can see the condition of the driver-side speaker in this video. I'm honestly surprised it was still working at all. I'm now driving a nightclub

 

[jackwhoo]

You should replace the 60amp fuse with a 15 amp fuse as soon as possible.

The complete circuit should be fused to protect the weakest part, 15amp

 

[GettinBetter]

... is rated for either 40 amps (3 core) or 35 amps (4 core) at 60 degrees...

That looks like something out of the 17th Edition, but I believe that refers to 230/400VAC which is not relevant for auto wiring (i.e 12VDC)

60Ax12V=720W , so I'm assuming the fuse is rated to deal with the inrush, or peak current during high volume low frequencies, still 60A seems a bit over the top to me, seeing as I vaguely remember reading that the system output is rated at ~100W, but low frequencies do require quite a bit of current if you want to give it a chance to perform to rated specs. The fuse protects the supply cable NOT the apparatus.

Speaker wires are usually thicker than expected/needed, to lower resistance and prevent voltage drops, but I've seen all sorts over the years, nobody seems to care.

Thats it, I'm rambling, give me another dwink.

 

[John202020]

60 is a bit overkill 30/40 would be fine for a single amp system, my old Honda had 4awg cable and 4 amplifiers, when I removed the set up from my mazda only a month ago I was slightly shocked that a cable connection ( try to never join a power feed cable ) had melted due to the current draw I regularly ran the system flat out ( adjusted to ensure no clipping/ distortion) allowing for efficiency was probably pulling more like 500+ Watts?
Any fuse should be 250mm from the battery. Any secondary fuse should have the shortest possible length between the thinner cable and thicker, ideally the thick cable terminates at the load or fuse holder?
Multiple amp systems often have a large capacitor 1 Farad or more at the amp panel to help cope with transient loads