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Thread: (2) ground wiring questions.
07-15-2011, 02:42 PM #11
07-15-2011, 02:55 PM #12Banned
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- Jul 2011
One #4 going into one #2 (with a manl fuse inbetween)
07-15-2011, 03:07 PM #13
07-15-2011, 05:45 PM #14'06 Supra Launch 20SSV-gone but never forgotten
07-15-2011, 09:12 PM #15
I look at assessing the cable size a little differently.
Start by determining the maximum and collective fusing for all amplifiers. Note, its unlikely that you will ever draw this much current. Even though you can exceed the fuse rating for a certain duration before it blows the amplifier total fuse amperage also represents an extreme operating condition to protect the amplifier.
Once you have the total max current draw plus the total distance of the main run for both positive and negative then you want a gauge of primary wire that has low enough resistance that you will not have an appreciable voltage drop.
Once you have the correct size of primary supply positive and ground you can drop down a size after the distribution blocks for the extensions to the two or three amplifiers. Since the distribution blocks are typically as close to the amplifiers as possible its usually the short extensions that are overkill for their actual usage.
You would have to have a ton of power or terribly inefficient amplifiers to compromise the amplifiers' performance using 2-gauge cable for a short primary run within the port locker. However, if there is considerable separation between the batteries and amplifiers this could change the requirements.
I would definitely trust 2-gauge to handle 150 to 200 amps of total potential draw over a couple of feet. And then step down to 4-gauge for the two or three very short individual extensions.
Remember that we may have an 8-foot positive and 8-foot negative for a total loop of 16 feet in many boats. A car may have a 17-foot positive run to the battery and a 2-foot negative run to the car body or frame. In many cars I would trust the longer 1 or 2-gauge ground cable before trusting the conductive properties of the car body.
So begin with the larger primary run based on your collective current draw. The smaller and shorter extensions at a step down in wire gauge are going to be plenty.