Blue for 24VDC?

Status
Not open for further replies.
L

lquadros

Member
I have a customer who wants to use exclusively blue wiring for all 24VDC circuits, for field wiring from a panel. The control panel is already wired in blue conductor. Is there a specific rule to use blue wires for 24VDC? Is there any code requirements? Thanks in advance for all your replies.
 
No requirement, but common. Blue is used extensively for low voltage DC control circuits. I use blue. Black for power conductors.

Since the panel is all blue, pick a color that you like. A striped wire would be a good choice, as it would be easy to identify. Like black with a blue stripe? If you could find some.
Stay away from orange, yellow, brown, red or black as these colors are usually ac.
 
lquadros said:
I have a customer who wants to use exclusively blue wiring for all 24VDC circuits, for field wiring from a panel. The control panel is already wired in blue conductor. Is there a specific rule to use blue wires for 24VDC? Is there any code requirements? Thanks in advance for all your replies.
Click to expand...

Many people follow NFPA 79 for machine control wiring.
Black = all line voltage AC or DC (power)
Red = all less than line voltage AC (i.e 120V control)
Blue = all less than line voltage DC (i.e. 24V control)
 
I design, wire, install, troubleshoot, etc. alot of control panels that have both 120AC and 24DC in them.

If I'm checking for the presence of 120AC, I usually use a solenoid type wiggy. Because it 'loads' the circuit a bit, it won't read induced phantom voltage like a digital meter will.

If a standard color code (like the one Jim stated above) is not used, it's easy to put the wiggy across the 120AC hot and a DC circuit. Then you have considerably more troubleshooting to do!

I stick with the color code, and label everything, it makes for a clean installation that's easy to add on to or repair.
 
:roll: Micromind "it's easy to put the wiggy across the 120AC hot and a DC circuit. Then you have considerably more troubleshooting to do! "

:D Sometimes all you have to do is follow the smoke trail, which isn't that hard to do.
 
We use wire with blue insulation for +24Vdc and blue with a white tracer for -24Vdc. This is a slight deviation from NFPA 79 14.2 which we follow but helps in wiring the machine correctly. If you use multi-conductor cable for field wiring this can be custom made with the same color scheme for about the same cost as off the shelf cable.
 
gwpowell said:
We use wire with blue insulation for +24Vdc and blue with a white tracer for -24Vdc. This is a slight deviation from NFPA 79 14.2 which we follow but helps in wiring the machine correctly. If you use multi-conductor cable for field wiring this can be custom made with the same color scheme for about the same cost as off the shelf cable.
Click to expand...
I've done a good bit of +/-12V and +/-15V, but all the 24 has been +24 and 0V. With +/-24V, what color is your 0V?
 
Status
Not open for further replies.
Top