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Old October 29th, 2002, 11:09 AM   #3
rsdoran
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Join Date: Apr 2002
Location: Birmingham, AL
Posts: 7,372
Personally I think if the 24vdc or any SOURCE/Reference voltage is using 2 specific colors those colors should NEVER be used to represent anything but SOURCE/Reference voltage.

I also prefer input wires to be a different color than output wires.

To me this makes the troubleshooting simpler, the maintenance/electrician will KNOW that the blue/white is a 0vdc reference to the blue 24vdc. IF a PB is being supplied by a blue/white then he knows that is a 0v reference and to check/verify can use the appropriate techniques. If you use the blue/white as an input wire from a PB then you lose reference points and it makes it more difficult to trace the circuit.

I go in cabinets daily that barely have more than all red or all black and it makes it slow to troubleshoot. The colors used do not matter that much (except for NPA and IEC conventions). WHAT does matter is that there is a method to the madness just like when writing code and documentation to explain.
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