paganrobert
Member
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- United States
I am trying to find where it is written as a standard that labels on control wires should read left to right and top to bottom?
Control Panel Wire Labels
- Thread starter paganrobert
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Interesting question. Since wires are sort of narrow I would think it to be quite logical that since it would be somewhat difficult to place a label on a wire that is read from top to bottom. As such I would be more practical to be read from left to right. But then you have another question to answer as to whether the source is to be toward the right or left which means if the writing is right side up or upside down.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Did someone tell you or imply to you that there is a standard? If you are in a facility with engineering specification standards of their own or working on an engineered project, and the specifications call for something like that, then you must comply. But I know of no industry standard that says you have to have wire numbers at all, let alone how they should be done.
When I did work at one plant for a large aircraft manufacturing company, they had a control wiring standard dictating that each wire termination had a printed tag that consisted of the 7 digit circuit number plus the terminal block number for the opposite end, which included the cabinet number or device number in it, each one was seven digits plus dashes. Every wire ended up with a wire marker that was about 2" long. Made it a real bitch when the wire was short. But when I went to another plant within that same company and did it that way, they wanted to know where I came up with that idiotic procedure. I told them I assumed it was a company standard, turned out it was just ONE plant engineer that demanded it at HIS plant. I think they ended up telling him to conform to what everyone else did, which was much more reasonable. The point of that was to illustrate that even within the same company, people expect different things.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
there is no such general requirement. In fact, IIRC, UL508a does not specifically even require wires have "wire numbers", only that they be identified in some way.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
BTW, I have noticed something new in AB MCCs.
The power wires in buckets are identified by dots of white paint on the wires. 1 dot for L1, 2 for L2 and none on L3.
The power wires in buckets are identified by dots of white paint on the wires. 1 dot for L1, 2 for L2 and none on L3.
Opinion
Opinion
This is the method i use in my shop since this question has come up many times.
For horizontal wires. All text reads left to right weather or not the wire terminates to the right or left.
Vertical can be a challenge but using the above as a guide. With the letters left to right rotate the wire clockwise. Now text reads top to bottom. This direction is used for wires that terminate going up or down. This kind of makes sense since "most" book spines read top to bottom (the proper way). For example on a book laying flat on a table writing is left to right. Now spin the book around and write some text on the spine left to right. Now open the book and position the text to read from left to right and tilt it up vertical so you can still read the text. The text on the spine now reads from top to bottom.
reading wire labels upside down or backwards just adds to accidents happening!
What makes you think there is an electrical standard for printing? Wires do not need to have "text" labels it is not in the code
Opinion
This is the method i use in my shop since this question has come up many times.
For horizontal wires. All text reads left to right weather or not the wire terminates to the right or left.
Vertical can be a challenge but using the above as a guide. With the letters left to right rotate the wire clockwise. Now text reads top to bottom. This direction is used for wires that terminate going up or down. This kind of makes sense since "most" book spines read top to bottom (the proper way). For example on a book laying flat on a table writing is left to right. Now spin the book around and write some text on the spine left to right. Now open the book and position the text to read from left to right and tilt it up vertical so you can still read the text. The text on the spine now reads from top to bottom.
reading wire labels upside down or backwards just adds to accidents happening!
What makes you think there is an electrical standard for printing? Wires do not need to have "text" labels it is not in the code
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paganrobert
Member
- Location
- United States
Direction of flow
Direction of flow
I have been told that the direction of the thermal labels will go in the direction of current flow. Top to bottom and left to right. Every panel shop I have worked in has followed the same "standard" although there is nothing in writing that I know of. Military aircraft do have the same direction as a standard. In control panels there should always be a wire label requirement as well as a wire color code requirement. It would be disastrous to a field service tech if the wires did not have any wire numbers and the color demonstrating voltage.
Direction of flow
I have been told that the direction of the thermal labels will go in the direction of current flow. Top to bottom and left to right. Every panel shop I have worked in has followed the same "standard" although there is nothing in writing that I know of. Military aircraft do have the same direction as a standard. In control panels there should always be a wire label requirement as well as a wire color code requirement. It would be disastrous to a field service tech if the wires did not have any wire numbers and the color demonstrating voltage.
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FWIW, we label at both ends from the terminal out, regardless of orientation. It may not always be the easiest way to read it but it is consistent. We also use colour coded ferrules so you can identify the numbers even if you can't read the digits.
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