Everything You Want to Know About UL651 PVC Conduit (2023)

For clean recycled materials or mixed materials, manufacturers must ensure that relevant standards are met, such as UL746D and UL-related standards.

Here we want to express our views. Although for the sake of environmental protection, using recycled materials or mixed production can reduce the waste of raw materials, the disadvantage is that it leads to a decrease in performance.

Then there will be a situation where many products on the market claim to be certified by relevant UL standards. Indeed, they also have compliance certificates. But in terms of performance, there is indeed a decline, such as stretch resistance.

Schedule 40 & 80 rigid PVC conduit and fitting are resistant to common corrosive influences, including alkali, hydrofluoric, and chromic acid vapors and mist, as well as pickling and electroplating, and meet the needs of users in these industrial scenarios.

Schedule 40 & 80 rigid PVC conduit and fitting inner walls should be smooth, and there should be no risk of burrs causing damage to the wires. Also, there should be no chips, blisters, cracks, spalling, scaling, chalking, or other defects on the outer surface of the tube.

The pipe body must keep the ordinate vertical and have no threads. Use a micrometer or tapered sleeve gauge to measure, the scale needs to be accurate to 0.001 inches or 0.01mm, and the measurement accuracy deviation should not exceed ±1%. The measured dimensions need to conform to the relevant specified dimensions. The relevant data already includes the tolerance range. The dimensions to be met include outer, inner, and wall thickness. In addition, like couplings, you need to measure the length, socket depth, etc.

The size requirements for Schedule 40 & 80 rigid PVC conduit are clearly described in Table 4.1. Generally speaking, the tolerance range of OD is ±0.004 to ±0.011 inch, while ID and wall thickness are specified minimum values to ensure that the required parameters are achieved.

For Type A & EB, the basic method is similar. The difference is that in this version, the OD and wall thickness of Type EB, the official description is that “Additional requirements will be added as these sizes are determined to be acceptable.”

For the quality requirements of accessories, UL651 also has some regulations, such as a smooth inner wall without burrs, which cannot affect the movement of wires. It does not allow debris, blisters, cracks, peeling, scaling, pulverization, or other defects.

UL 651 also specifies the maximum and minimum values of length, wall thickness, Socket diameter, and other parameters for all accessories to match rigid conduit. For example, for Coupling for Type EB and A conduit, under the condition of 1/2 to 6-inch trade size, the average tolerance of Inside diameter at the inner end of the socket is ±0.008 to ±0.014 inch, while the average tolerance of Inside diameter at the entrance to the socket is ±0.015 to ±0.023 inch, and the size requirements are specified in the relevant table.

There are also some special ones, which we will briefly list here. For example, in a threaded adapter suitable for threaded PVC wire and tube, the thread must be clear and clean, and the size needs to meet the requirements of ASME B1.20.1-1983. At the same time, the threaded port should have enough field and meet the bending test.

Because there are too many accessories, we will not list them here.