European Wire Colors

[Tim Ganz]

I got a panel in today built in the U.S. and it has Brown wire for 24 VDC + and Blue wire for 24 VDC-.

Is this the European standard? I have seen prox sensors with that wire coloring before but this is the whole panel. Did not seem right to me but I have not dealt with many forgein panels. But as I said this was built in the U.S. by a U.S. Founded and owned company.

Is this correct for Europe?

 

[LadderLogic]

Yes, this is a European standard (I am sure someone can point to an IEC standard number) and it's been quite popular in the US as well.

 

[boneless]

We normally use RED for 24 VDC+ and BROWN for 24 VDC-. BLACK for 230 VAC and BLE for neutral. This is in Norway. However we have clients demanding other colors. BLUE and WHITE-BLUE for 24 VDC+/-.

Check with your client and check the standards you are using. DnV / NorSok / TuV they all got their guidelines.

 

[James Mcquade]

Tim,

I would consider purchasing a copy of NFPA 79, standard handbook for electrical machinery. around $30 and well worth it.

you can google nfpa79 and find an older pdf copy.
it covers the electrical color standards for control wiring.

regards,
james

 

[nonuke]

The only colors in the European standard are:

Black: L1, L2 and L3
Light Blue: N
Green/Yellow: PE
Orange: Cable powered from an outside equipment.

All other wire colors for: 24VAC, N24VAC, 24VDC, 024VDC, PLC inputs, PLC outputs etc... since are for low voltage, don´t have a standard. We supply with all of our schematics, a list of all the wire colors and their meaning.

The above colors are for wires inside the panel, not for cables.

 

[kamenges]

NFPA 79 in the U.S. is very similar in requirement. However, even the incoming supply conductors don't need to be black as long as they are marked in some other way.

NFPA 79 14.2.4 uses the following phrase with respect to wire colors:
"Where color is used for identification...", after which it goes on to specify a few other general color requirements.

As in Europe, the following conductors have designated colors that should not be violated:
PE: green or green w/yellow stripe
Grounded Conductor (AC common): white or gray
External ungrounded conductors: orange or yellow

Outside of that you are on your own.

Keith

 

[Tim Ganz]

So the Brown wire for 24 VDC + and Blue wire for 24 VDC-. is not an IEC standard? I knew what the NFPA was. Only confusion there is I see equipment with the -24 being blue wire with a white tracer and I also see it in some equipment as a white wire with a blue tracer.

IIRC the NFPA calls for White with a blue tracer.

Also from this Thread http://www.plctalk.net/qanda/showthread.php?t=89635

I am trying to determine what color I should make the 120 volt Neutral since it will be live with the disconnect in the off position? I know the hot wire should be colored orange and I have labels for the door that indicate voltage is still present when disconnect is off and is fed from another system.

But do I make the Neutral white or Orange?

 

[Bering C Sparky]

External ungrounded conductors: orange or yellow

If Keith is quoting this from code then you would leave the neutral white.
Above quote says "ungrounded conductors" a neutral is a grounded conductor so would not apply.

I never knew about the orange or yellow for external conductors, interesting, need to get a copy of NFPA 79 for myself.

Regards,
BCS

 

[James Mcquade]

Tim,

when did the 120 volt wiring come into play on this post?
I think you have posted to this post incorrectly.

when the disconnect to a machine is turned off, all power wiring is disconnected!

if the power is from another source, the precautions I stated in your hydraulic pump post applies.

Leaving the neutral connected when the power is off WILL get someone hurt!
when that happens, the end user will come looking for the oem who built the equipment and they will look for you!

I don't have the exact details in regards to this post in regards to the 120 volt wiring, but when the neutral backfeeds
the controls or you end up with a floating neutral / ground voltage, someone can get hurt.

I worked for an oem who was installing some equipment and found this out the hard way. everytime we pulled the trigger on a drill motor, we got lit up good.

there was a 75 volt floating neutral in the plant.

regards,
james

 

[moggie]

Have a look at this post -

http://www.plctalk.net/qanda/showthread.php?t=29474

 

[kamenges]

Tim-

According to NFPA 79 14.2.3.2 (2), the neutral for externally supplied conductors would be white w/orange stripe or white w/yellow stripe, depending on the ungrounded conductor color.

Keith

 

[Mill_Control]

I got a panel in today built in the U.S. and it has Brown wire for 24 VDC + and Blue wire for 24 VDC-.

Is this the European standard? I have seen prox sensors with that wire coloring before but this is the whole panel. Did not seem right to me but I have not dealt with many forgein panels. But as I said this was built in the U.S. by a U.S. Founded and owned company.

Is this correct for Europe?

Brown + and Blue neutral is a european AC power cord color scheme but I don't know if it's actually a standard. Quite often seen on prox leads and such too.

I've never seen that color scheme used for internal DC control panel wiring though. And I've seen my share of euro, and asian, panels.

 

[RussB]

The Europeans don't use "colors".

They use "colours", I think it has to do with the hue, or it may be the dew that has to do with the hue?

 

[seppoalanen]

Have a look at this post -

http://www.plctalk.net/qanda/showthread.php?t=29474

In my mind JesperMP's post #8 is correct.

"What I have from EN60757 (which is linked to from EN60204-1), but maybe is not up-to-date, is this:
BLACK: AC and DC power circuits
RED: AC control circuits
BLUE: DC control circuits
ORANGE: interlock control circuits supplied from an external power source.
YELLOW/GREEN: Protective ground.
And that is it. There is nothing more."

 

[ojz0r]

White is often used for analog signals.