What guage wire to use?

Hi I am new here and I have a question. I am installing an air horn on my motorcycle, and I want to know what gauge wire to use. The compressors ratings are as follows: 12VDC, 10 watts, 8 ohms The relay that is used is a 40 amp The fuse that needs to be used is a 30 amp The power wire going to the compressor is going to be about 2 feet in length. Another question, what type fuse should I use? There is not a fuse supplied, so I don't know what will work well. Is an inline fuse going to work for what I need? Thanks for your help, I really appreciate it.-Chris

2001 Suzuki SV650

yes an inline fuse will work as long as you place it right at the source of voltage (battery,etc). The guage of the wire can be 12 guage this should work fine for what you need! On a side note that horn will never draw 30 amps!! But if it is recomended by the manufacturer than do it. I would use a smaller value fuse and then see if it blows if not leave it maybe a 15 or 20 tops.

Why does it matter where the fuse goes? How much current is going to going through the wire? I tried figuring it out, but I kept getting different numbers when I tried different variations of V=IR What is the Eq for watts? Can you tell that I know nothing about electricity?-Chris

2001 Suzuki SV650

The fuse should always be close to the source of volatage because of shorts if the wire shorted on metal the wire would start to burn from the source if the fuse is close it can stop the burn before it is farther down the wire.(basically trust me and place the fuse near the battery so u and your car will be happy) With the figures u gave it would have about 1 amp of current flowing through it. But its better to have bigger than needed than have too small so use 14 guage wire for the horns. Im sure that they will never draw more than 10 amps. The current draw will change though at times and this is the reason why you need more is to operate the compressor at startup- the current may be around 10-20 amps but once going it will be much less. When a motor starts up it draws a substantial amount of current as compared to when it is running. What is the Eq for watts? power is the equvilant of watts Can you tell that I know nothing about electricity? You sound like you want to learn this stuff better that sounds good to me!

oh by the way a 14 guage wire will handle 35 amps at the distance of 2 feet u mentioned!

Thankyou for the quick replies, I was just wondering about the fuse placement. I wasn't trying to disagree. By "Eq for watts" I meant Equation, I should have been more specific. I think it is P=IV, but I am not sure 14 guage sounds great, Do I need to solder it or will spade and slot connections be good enough?-Chris

2001 Suzuki SV650

Soldering is always best, Then you will have no problems if you have a sodering iron then go right ahead and solder.Butt connectors will do as long as they are done corect. For all the ohms law use the calcualtors they have on this site in the basic menu on the top left corner. Yes 14 guage sounds great and it will not be to thick (easier to work with) By the way I did not think u were did not believe me about the fuse ,

I am installing the air horn on my motorcycle. Its a safety device so all you cagers out there don't run me over This is my bike. Its in the modification process -aka Winter -Chris

2001 Suzuki SV650