Question on 12V Wire Color Convention

[minuteman62-64]

First, let me say that it's done, it works, and if it's wrong I'm the only one who will know

I wired up an overheat alarm for my outboard. Ran 12V+ to one terminal of a buzzer, mounted on the console, with other terminal of the buzzer going to a thermostatic switch on the motor, with ground to the motor. I also have a momentary contact SPST switch in the console to temporary ground the down current side of the buzzer for a test.

I'm familiar with the basic 12V wire coding, with red from 12V+ and black to 12V-. So, my logic (???) was that terminals that would be hot (12V+) under non-operational conditions (test switch not engaged or thermostatic switch not tripped) should be wired with red wire and returns to ground should be wired with black wire.

Attached diagram shows the color scheme I used. Did I get it right?

 

[Silvertip]

Re: Question on 12V Wire Color Convention

You are sort of correct but there are more to circuits than just positive and negative. Red is not the ONLY color for a "feeder" or "line" circuit. So: On a boat, red is typically used to signify power from a source to the first item in a circuit. This may be a single switch, a gang of switches or in your case, the alarm horn. That wire may be brown instead of red and still be appropriate. The "load" side of a circuit (the device side of a switch for example) can use red wire as well but that is not a requirement. Circuits can be identified by other wire colors depending on what those circuits control. In your case, the wire between the buzzer and the thermo switch on the engine should be brown if you want it to conform to typical outboard wiring. If the thermo switch has a separate ground lead then it could be black. If the switch itself has the shell as the ground no wire is needed. The +12 volt feed to the gauges on your boat is purple and not red. The line between the fuel tank sender and the gauge is pink. All of this for circuit ID. Your alarm works and you are happy with that so nothing else matters. Electricity doesn't care what color the wires are but those who need to troubleshoot it sure wish things were not altered.

 

[minuteman62-64]

Re: Question on 12V Wire Color Convention

You are sort of correct but there are more to circuits than just positive and negative. Red is not the ONLY color for a "feeder" or "line" circuit. So: On a boat, red is typically used to signify power from a source to the first item in a circuit. This may be a single switch, a gang of switches or in your case, the alarm horn. That wire may be brown instead of red and still be appropriate. The "load" side of a circuit (the device side of a switch for example) can use red wire as well but that is not a requirement. Circuits can be identified by other wire colors depending on what those circuits control. In your case, the wire between the buzzer and the thermo switch on the engine should be brown if you want it to conform to typical outboard wiring. If the thermo switch has a separate ground lead then it could be black. If the switch itself has the shell as the ground no wire is needed. The +12 volt feed to the gauges on your boat is purple and not red. The line between the fuel tank sender and the gauge is pink. All of this for circuit ID. Your alarm works and you are happy with that so nothing else matters. Electricity doesn't care what color the wires are but those who need to troubleshoot it sure wish things were not altered.

OK, got it. Thanks. Appears changing the wire from the buzzer to the thermo switch from red to brown would be a major step towards conformity. As with everything I put together, I expect I'll be modifying this some day. I'll include that change in the agenda at that time.

In the meantime, I've only got two circuits running from the console back to the motor - this one and one from my cylinder head temperature sensor. They are both different colors (this one red, I won't disclose the color of the other ), so there won't be any problem troubleshooting.

 

[frankk]

Re: Question on 12V Wire Color Convention

Folks, where can I find the "color code" URL?

 

[dingbat]

Re: Question on 12V Wire Color Convention