Allied Encyclopedia: Dual-rated Cable

Allied EncyclopediaFinding the right wire to suit your specific needs can be a complicated process as it is—it doesn’t help that one wire can have several different names.  A lot of wire and cable is named according to the industry approvals it meets, so the same cable product can actually fall under multiple categories and be referred to in many different ways.  It can be confusing, but with a better understanding of dual-rated cable, you should feel more confident in your wire and cable selections.

What does it mean when a part is marked as dual-rated?

Truthfully, it could mean a number of the things, but the simple answer is this: a dual-rated product meets more than one industry standard. Industry standards are designed to regulate quality and safety in products such as wire and cable. These standards are established by a variety of national and international organizations, some of the most well-known being UL, NEMA, CSA and SAE. For more on these organizations, visit the Standards Organizations page on the AWC website.

A wire or cable doesn’t need to match the exact parameters identified in the standard—it just needs to meet or exceed the minimum ratings and adhere to construction specifications in order to be considered compliant with industry standards. For this reason, it’s common to see one cable product listed with multiple ratings and what may seem like huge disparities in voltage or temperature ratings. Those ratings are associated with the different industry standards and are not necessarily the maximum capabilities of the cable, so it’s important to check specs in their entirety.

For example, AWC’s M16878/5 mil spec hook-up wire is dual rated UL 1180 cable/NEMA HP3 Type EE cable, meeting both NEMA standards as well as UL standards for wires smaller than 8 AWG. It is considered suitable for internal wiring applications with high frequencies and temperatures.

UL 1180- Type EE product listing

Click on the image above to see the full product page.

The conductor is stranded silver plated copper wire insulated with extruded Polytetrafluoroethylene (PTFE). The designation of UL 1180 cable means the wire is rated up to 200°C and 300 volts. In contrast, the NEMA HP3 Type EE cable designation signifies that NEMA rates the wire up to the same 200°C, but the voltage rating is bumped up to 1000 volts. That’s a fairly significant difference in voltage. Of course, the actual capacity of the wire doesn’t change, only its use. Each organization rates products according to the purposes of their industries. NEMA standards often apply to larger scale applications requiring higher voltages, so NEMA tests and rates the wire at higher levels than UL does.

You may also find M16878/1 hook-up wire with a dual rating of UL1061/Type B cable. This wire is made of solid or stranded tinned copper with extruded S-R PVC insulation.  This meets the UL 1061 cable standards, which specifies wire with a single 30 AWG-14 AWG conductor. Wire gauges that fall outside of that range are not included under the standard.  UL 1061 cable is rated up to 80°C and 300 volts.

The same cable is also categorized as Type B wire, as outlined in the MIL-DTL-16878/1 specification. Like the UL standard, M16878/1 mil spec specifies a single conductor with extruded PVC insulation, but with a range of 32 AWG-14 AWG, it covers a larger range of sizes than the UL 1061 standard. In addition to dual rated wires meeting AWG size requirements, dual rated UL wires must also have overall diameters (O.D.s) that fall within the range specified by the mil spec. The mil spec standard rates the wire up to 105°C and 600 volts, so what AWC identifies as UL1061/Type B cable complies with these requirements as well. It is important to note that a Type B wire with a 32 AWG conductor would not meet the UL 1061 dual rating that only goes down to 30 AWG. It is also important to be aware that not all M16878/1 parts fall in the same category with the dual-rated cables discussed here—we are talking only about tinned copper conductor Type B wire, even though the same M16878/1 mil spec cable standard also covers wire with silver-coated high strength copper alloy conductors, represented with a “D” in the part number. Meanwhile, UL 1061 doesn’t specify any particular conductor material.

But that’s not all. The same wire can also meet another UL standard, depending on its gauge. Wires with sizes between 32 AWG and 16 AWG meet UL 10002, rating them up to 105°C and 300 volts. Again, these ratings are not necessarily indicative of the wire’s actual capacity, rather the needs of the industries and/or applications using it.

The key to wrapping your head around dual-rated cable is recognizing that the scopes of standards differ, whether the scope is the range of products included under a standard or the range of part sizes rated. Check out the chart below to see the standards side-by-side. It might help!

 

Wire Size

Conductor

Temperature Rating

Voltage Rating

MIL-DTL-168787/1

Type B

32 AWG-14 AWG

Solid or stranded
single conductor; tinned copper

105°C

600V

UL 1061

30 AWG-14 AWG

Solid or stranded
single conductor

80°C

300V

UL 10002

32 AWG-16 AWG

Solid or stranded
single conductor

105°C

300V

 

If you’re finding even more confusion surrounding dual-rated mil spec cable than other dual-rated varieties, there’s a reason for that. In addition to the multiplicity of names and ratings that come with the territory, changes in mil spec standards introduced new terminology without fully erasing the old. Many mil specs have technically been replaced by non-government standards developed by organizations such as NEMA and SAE. The M16878 cable standards, as seen in the first example, have been replaced by the NEMA HP3 cable standards. Though they aren’t always current, people in the industry still widely use the mil spec numbers to identify certain kinds of wire and cable, so the numbers hang around.

Still baffled by dual-rated wire and cable? Contact your Allied Wire and Cable representative with questions about our dual-rated products.

About awcwire
Allied Wire & Cable is a value-added manufacturer and distributor of electrical wire and cable, tubing, and more. We are a family owned and operated company, serving a wide range of industries, including the military, automotive, aerospace, and telecommunications markets. Allied is headquartered in Collegeville, PA. Additional locations can be found across the US, in Merrimack, NH, Tampa, FL, Pewaukee, WI, and Las Vegas, NV. For more information on Allied, visit our main website at www.awcwire.com.

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