24VDC brown blue

I was working with a group of engineers for Motorola and one ‘Know It All’ supervisor dictated that “there is no color code standard for low-voltage DC wiring” and he proceeded to define his own coding. By chance it started with wire1= black, wire2= red, etc. I tried explaining there was a standard but he wasn’t listening.

A quick look at the wiring and it was obvious the non-standard wiring had got us. The fan cables, per the old telecom standard, used red for 24Vdc and black for dc common. But the tech followed the non-std rule and connected black to pin1 (24Vdc) and red to pin2 (common) and of course the fans did not rotate. We came close to blowing out an expensive CO2 laser tube due to one engineer’s refusal to note wire color codes from the late 1950s. I guess the guy never opened a portable radio or used a 9V battery.

Iecwire color

JavaScript seems to be disabled in your browser. For the best experience on our site, be sure to turn on Javascript in your browser.

Strobes and flashing LEDs are ultra-bright, high impact warning lights for trucks. Most lights are available in red, amber, clear and blue. All of our lights feature brilliant flash patterns that grab the attention of passing motorists well before they encounter your truck on the side of the road. Safety is paramount when you are working in traffic, and you can never have too many blinking lights on your truck - but if you don't have enough... look out.

NOTES: the above chart was derived from NFPA-79 and EN-60204 wiring codes for low-voltage electrical panels. They have limited use since they're focused on industrial applications from years ago. So I added wire colors from the PC industry (ICEA power supply std) to cover lower voltages seen on modern machinery. There are a few conflicts since the industrial & computer designers are not communicating. (Perhaps IEEE can address this issue some day.) Please understand that many devices that only use one dc voltage will use red/black wires for +/- voltages. Using the ATX color code improves systems that use more than one low voltage. Consider the type of equipment you are wiring when using this chart. NFPA & EN colors are good for machine & robot electrical cabinets (panels), and ATX colors work well with computer & electronics due to the variety of dc voltages (ATX even covers negative voltages). Note that many signal cables use all black or white colors that are numbered. But you can still use proper wire colors when these cables terminate to a connector (terminal block). This way devices wiring can match the defined colors. Also note, the U.S. and Euro device wiring is different: U.S. uses red/black/white for device power, common & signal wires; while Europe uses brown/blue/black for power, common & signal wires.

Finally, this chart does not cover AC circuits or DC high-voltage (>30V) power circuits. Refer to NEC & NFPA-79 standards for more information. If you have questions, or need more details on the low-voltage DC wiring contact Bill Egert at Logic One, LLC.

24VDCwire color codeUSA

If you’ll recall I wrote a post about color codes for pneumatic tubing last year (July, 2018 post). Now it seems time to talk about DC wire colors.

We had designed a CO2 laser marking system for ‘printing’ barcode and 2D matrix onto printed circuit boards and the assembly techs were finishing wiring. They powered on the machine and one tech noticed the CO2 tube fans were not running. Good news he saw that because the fans cooled the CO2 tube to keep it from breaking, and the tube cost over $10,000.

24VDCwire color codeIEC

So save your team some time and money and show them the low-voltage DC wire color codes from the above chart. And remind them most PCs, electronics, & radios use this standard. So why don’t they? It sure beats having your machine or robot fail, and it’s less confusing for maintenance techs.

Anyhow, many electrical designers will lay-out their low voltage cables starting with DC voltage first, DC common second, and switched DC voltage third, then signal wires following for as many wires as needed.

TrucknTow takes your security and privacy seriously. To learn more about the data we collect, please review our Privacy Policy.