Thoroughly labeled electrical conduit helps save time when troubleshooting, improves safety, increases efficiency, and helps avoids costly mix-ups. It makes your job easier.
Are there standards for labeling electrical conduit? Not specifically. However, the ANSI/ASME A13.1 pipe marking standard provides the label and text sizes that are appropriate for labeling electrical conduit.
The ANSI Z535 standard defines the colors that should be used for safety related labels. For example, yellow with black printing should be used for cautionary labels and orange with black text for warning labels.
Standard for Label & Text Size Based on Conduit Diameter
| Outside Conduit Diameter |
Minimum Length Label |
Minimum Letter Height |
| Inches |
mm |
Inches |
mm |
Inches |
mm |
| .75-1.25* |
19-32 |
8 |
203 |
0.5 |
13 |
| 1.5-2 |
38-51 |
8 |
203 |
0.75 |
19 |
| 2.5-6 |
64-152 |
12 |
305 |
1.25 |
32 |
| 8-10 |
203-254 |
24 |
610 |
2.5 |
64 |
| >10 |
>254 |
32 |
813 |
3.5 |
89 |
There are no codes that specify the quality of electrical conduit labels. However, conduit labels that don't last might as well not even be there. You've wasted your time. Typical electrical conduit labels should be resistant to abrasion, moisture, dirt and cleaning fluids. Outdoor electrical conduit labels must be resistant to weather and fading in sunlight. Electrical conduit labels in other locations may need to be resistant to oil, grease, extreme temperatures and other harsh environmental conditions.
Electrical conduit should be labeled with the voltage, an ID number, and the locations that the electrical conduit connects from and to. Labels should be placed at both ends of the conduit, at junction boxes, and any other location where information about the wiring in the conduit might be needed.
Several labels may be used to supply all of the needed information. For example, an orange warning label with the text "480 Volts" might be used. An arrow may be used to indicate the direction of power flow, from the source to the point where the power is distributed or used.
A second label, white in color, may be used to identify the purpose, source and destination of the conduit. The label with the voltage is orange because it is a safety related label informing about the voltage hazard. The second label is white because it is an informational label.
Labeling Smaller Electrical Conduits
Labeling smaller conduit, that is one inch or less in diameter, may be difficult because labels may fail as a result of being applied to a tightly curved surface. Or, in order to make labels that fit, the labels are very small. The answer is to use self-laminating labels such as DuraLabel wire wraps. These are labels with a printable area and a clear tail that wraps around the conduit and covers the printed label. Since the label wraps completely around the conduit it tightly adheres and is durable. In addition, the clear tail protects the label from dirt, dust, moisture, cleaning fluids, sunlight and other environmental conditions that might have shortened the label life.
Getting the Right Supplies for Labeling Electric Conduit
DuraLabel is the only brand of label printer that always has the right supplies for labeling electrical conduit. Whether you need continuous vinyl, self-laminating wire wraps, or special low temperature labels that will withstand frigid arctic winter temperatures, DuraLabel has the right supply. With many types of labeling supplies, DuraLabel has more types of supplies than any other label printer brand. That means you can always get the right supply for the job.