Plc I/o -color Coding Help

[DCI]

Hi again blokes!

We are building an industrial control panel, in Australia, for use in Nth Dakota. I have read NFPA79 and UL508A, but would still like some further confirmation / thoughts on the matter, with regards to color coding.

UL508A (66.5) says in "industrial machinery" control panels .....Blue all ungrounded DC conductors, .....White w/Blue stripe all grounded DC conductors.

My usual practice on 24VDC systems is to differentiate between wire function, using colors.
for example:- hard connected positives say Blue, grounded negatives say Grey / Blue stripe, DC inputs say Yellow & DC outputs say Brown. Naturally all wires have numbers as well.

Is this OK, or should I just make all of the inputs & outputs Blue?

Sorry to ask a question that is so similar to those that have been posted before.

Many thanks for your time.

Gavin

 

[don_resqcapt19]

I think that yellow is reserved for wires that have a power source that originates outside of the PLC panel.
Don

 

[petersonra]

Hi again blokes!

We are building an industrial control panel, in Australia, for use in Nth Dakota. I have read NFPA79 and UL508A, but would still like some further confirmation / thoughts on the matter, with regards to color coding.

UL508A (66.5) says in "industrial machinery" control panels .....Blue all ungrounded DC conductors, .....White w/Blue stripe all grounded DC conductors.

My usual practice on 24VDC systems is to differentiate between wire function, using colors.
for example:- hard connected positives say Blue, grounded negatives say Grey / Blue stripe, DC inputs say Yellow & DC outputs say Brown. Naturally all wires have numbers as well.

Is this OK, or should I just make all of the inputs & outputs Blue?

Sorry to ask a question that is so similar to those that have been posted before.

Many thanks for your time.

Gavin

I think the unusual color coding scheme would be confusing for future users. Best to stick to what the standard says. In the unlikely chance it gets inspected, rewiring it in the US would be expensive for you.

Stick to UL listed components, including the wire, and you should be OK.

To make it easier to maintain, avoid using components that are not readily available in the US, or cannot be easily substituted for. For instance, some fuses I see on stuff coming from overseas are difficult to find here.

Technically, the control panel should be UL listed, although very few plants enforce this requirement.

 

[DCI]

Thanks for the comments Bob & Don

Thanks for the comments Bob & Don

From your feedback I am now going to make all non-grounded 24VDC Blue.

The panel is 100% UL components, (including wire) & I am
aiming for 100% UL compliance with the 24VDC. The panel is to be inspected for UL compliance on arrival to the US.

We had reserved Orange for external 110VAC control supplies that originate outside the panel or those not disconnected via the Main disconnect. Should this become Yellow?

Note: 480VAC colors have been reserved for Black, with Brown Orange & Yellow heat shrink on the ends.

One final query....the non-grounded 110VAC is to be Black with a heat shrink identifier while the grounded 110VAC is to be white. What is the most acceptable colour for the above identifier?

Cheers,

Gavin

 

[petersonra]

From your feedback I am now going to make all non-grounded 24VDC Blue.

The panel is 100% UL components, (including wire) & I am
aiming for 100% UL compliance with the 24VDC. The panel is to be inspected for UL compliance on arrival to the US.

We had reserved Orange for external 110VAC control supplies that originate outside the panel or those not disconnected via the Main disconnect. Should this become Yellow?

Note: 480VAC colors have been reserved for Black, with Brown Orange & Yellow heat shrink on the ends.

One final query....the non-grounded 110VAC is to be Black with a heat shrink identifier while the grounded 110VAC is to be white. What is the most acceptable colour for the above identifier?

Cheers,

Gavin

I'd be inclined to use red for the ungrounded 120V stuff.

The most common "identifier" is a heat shrink or wrap-around wire marker with the wire number printed on it. they are not normally color coded.

Yellow would be anything that could potentially be energized with the cabinet disconnect open. the most common things are externally powered circuits, but it is common for PLC itself and internal cabinet lighting circuits (etc.) to be wired to the line side of the disconnect.