Post by HONDAM on Apr 8, 2012 18:26:51 GMT -5
"What size wire do i need for..." This is a very common question and one a lot of people guess at but there is a meathod to choose best for safety and reliability. It is easy to do with a little bit of multiplication and a chart.
First you have to start with how much power you have to handle. Weather it is a single item or rigging up a fuse panel everything has a max amperage rating just add it all up. For this example lets say your rigging up a fuse panel and want it to be able to handle 30 amps.
Now you have to figure length. They call it a circuit for a reason the engery flows to and from the power source so if you just measure from the battery to the fuse panel one way and its 10 feet you have to double it to 20 feet to take into account the entire circuit there and back.
So you have 30 amps and 20 feet of wire. Multiple the two and you get 600.
Then you go to the chart.
The rows that you are looking at are labels Famps and in most cases the 12 volt section. Now when your deciding weather to follow the 3% or 10% collums take into account what this circuit is being used for. This area is left up to some degree of interpritation. The 3% column is very critical items that immediately affect the safety of the vessal like running lights, bilge pumps, or the fuse panels that power them. The 10% column is for most other loads.
So say this fuse panel your wiring is powering your entire dash which include the switches for running lights and bilge pumps you follow down the 3% column until you get a number over 600 used in our example and you will need to use 6 gauge wiring. But say this fuse panel is only powring a stereo, fishfinder, some spreader or courtasy lights, nothing critical to your safety, then follow the 10% column and looks like 12 gauge is enough. Now this is a minimum for consideration just because the chart says 12 doesnt mean you cant step it up to 10 gauge.
Also after you have chosen your wire alway remember to fuse it, in this example we figured on 30 amps so i would put a 30 amp breaker in the line to protect against shorts.
I hope i didnt complicate it to bad and everyone understands, let me know if you have any questions.
First you have to start with how much power you have to handle. Weather it is a single item or rigging up a fuse panel everything has a max amperage rating just add it all up. For this example lets say your rigging up a fuse panel and want it to be able to handle 30 amps.
Now you have to figure length. They call it a circuit for a reason the engery flows to and from the power source so if you just measure from the battery to the fuse panel one way and its 10 feet you have to double it to 20 feet to take into account the entire circuit there and back.
So you have 30 amps and 20 feet of wire. Multiple the two and you get 600.
Then you go to the chart.
The rows that you are looking at are labels Famps and in most cases the 12 volt section. Now when your deciding weather to follow the 3% or 10% collums take into account what this circuit is being used for. This area is left up to some degree of interpritation. The 3% column is very critical items that immediately affect the safety of the vessal like running lights, bilge pumps, or the fuse panels that power them. The 10% column is for most other loads.
So say this fuse panel your wiring is powering your entire dash which include the switches for running lights and bilge pumps you follow down the 3% column until you get a number over 600 used in our example and you will need to use 6 gauge wiring. But say this fuse panel is only powring a stereo, fishfinder, some spreader or courtasy lights, nothing critical to your safety, then follow the 10% column and looks like 12 gauge is enough. Now this is a minimum for consideration just because the chart says 12 doesnt mean you cant step it up to 10 gauge.
Also after you have chosen your wire alway remember to fuse it, in this example we figured on 30 amps so i would put a 30 amp breaker in the line to protect against shorts.
I hope i didnt complicate it to bad and everyone understands, let me know if you have any questions.