Labeling requirement for internal circuits in an industrial control panel?

[cycle61]

Question contained mostly in thread title...we're evaluating a transformer control panel built by a major manufacturer which inexplicably has absolutely no labeling whatsoever on internal control circuits. UL508a seems most applicable to the equipment, and although it has requirements for labeling field wiring and to have a schematic, I'm not seeing anything in the UL or NEC explicitly calling out that internal control wiring be labeled.

 

[petersonra]

Question contained mostly in thread title...we're evaluating a transformer control panel built by a major manufacturer which inexplicably has absolutely no labeling whatsoever on internal control circuits. UL508a seems most applicable to the equipment, and although it has requirements for labeling field wiring and to have a schematic, I'm not seeing anything in the UL or NEC explicitly calling out that internal control wiring be labeled.

That's because labeling of wires is not required.

 

[cycle61]

That's because labeling of wires is not required.

That...hurts my head. Perhaps I've just been spoiled by modern datacenter project requirements. This is the first time in better than a decade I've seen a new control panel with no wire labels.

 

[jim dungar]

I have supplied equipment to many different companies most of which had their own idea of what constituted proper labeling of wires. They were all surprised their idea was not the standard methodology. The process and automation people had a very hard time with the labeling methods used in switchgear harnesses.

If you want something you need to make sure it is in your contract, you might be surprised at how many company standards are not enforced by those whose job it is to watch the budget.

 

[qcroanoke]

I have supplied equipment to many different companies most of which had their own idea of what constituted proper labeling of wires. They were all surprised their idea was not the standard methodology. The process and automation people had a very hard time with the labeling methods used in switchgear harnesses.

If you want something you need to make sure it is in your contract, you might be surprised at how many company standards are not enforced by those whose job it is to watch the budget.

We used to. Production whined it took to long but it sure made trouble shooting easier.
I think they are back to doing it now but a lot of it is customer specification driven

 

[TwoBlocked]

NFPA 79 has requirements for labeling and drawings, but not what the labeling scheme or drawings should be like. Wait, I think it might include examples. Been a while.... But I think its "scope of application" is for a machinery manufacturer, not in-house work. It could be argued that the NEC article about craftsmanship like work would require conductor labeling.

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