What Is SIS Wire?

SIS wire is a range of single-core wires with cross-linked polyethylene insulation (XLPE) for use in electrical switchboards and panels with voltages up to 600v. The National Electrical Code (NEC) Table 310.104(A) describes type SIS wire as switchgear and switchboard wire with flame-retardant thermoset insulation for use at temperatures up to 90 degrees Celsius. This wire is dual rated with several UL standards and complies with the Canadian Standards Association (CSA) SIS and CL1251 types.

30 items

  • SIS-18-16T
    $0.00 / 1000 FT
    • Approx LBS/MFT: 10.00
    • AWG Size: 18
    • Cond. Material: Tinned Copper
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  • SIS-18-1T
    $0.00 / 100 FT
    • Approx LBS/MFT: 256.00
    • AWG Size: 18
    • Cond. Material: Tinned Copper
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  • SIS-18-7T
    $0.00 / 1000 FT
    • Approx LBS/MFT: 0.00
    • AWG Size: 18
    • Cond. Material: Tinned Copper
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  • SIS-16-1T
    $0.00 / 1000 FT
    • Approx LBS/MFT: 0.00
    • AWG Size: 16
    • Cond. Material: Tinned Copper
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  • SIS-16-26T
    $0.00 / 1000 FT
    • Approx LBS/MFT: 13.00
    • AWG Size: 16
    • Cond. Material: Tinned Copper
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  • SIS-16-7T
    $0.00 / 1000 FT
    • Approx LBS/MFT: 0.00
    • AWG Size: 16
    • Cond. Material: Tinned Copper
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  • SIS 14-41T-8 VW-1
    $0.00 / 1000 FT
    • Approx LBS/MFT: 20.00
    • AWG Size: 14
    • Cond. Material: Tinned Copper
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  • SIS-14-1T
    $0.00 / 1000 FT
    • Approx LBS/MFT: 0.00
    • AWG Size: 14
    • Cond. Material: Tinned Copper
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SIS Wire Construction

SIS wire is a single conductor insulated wire without a jacket.

Conductors

All SIS wires supplied by Allied Wire & Cable (AWC) have tinned copper conductors. Conductors may be solid or stranded. Sizes go from 18 American Wire Gauge through to 4/0 American Wire Gauge (AWG). Wires between 18 AWG and 12 AWG may have solid or stranded conductors, while larger sizes have stranded conductors. Typically, you can choose between relatively stiff seven-strand wires or more flexible wires with multiple fine wire strands.

Insulation

All wires have XLPE insulation. XLPE is a thermoset material that does not shrink when cut back or heated. It is tough and resists moisture, chemicals, and oil. XLPE is naturally fire-resistant and most SIS wires from AWC have WV-1 fire certification.  

SIS Wire Applications

SIS wire is for use in dry locations for wiring electrical switchgear, control panels, substations, and equipment only. The NEC SIS category covers wires between 14 AWG and 4/0 AWG, and the maximum temperature that's allowed is 90°C. The lower size limit for SIS wires is 14 AWG, so wires between 18 AWG and 14 AWG have this marking: "Suitable for switchboard use."  

SIS Dual Ratings

Many SIS wires have dual SIS and UL ratings. These include: 

  • UL 3173: This wire is suitable for internal appliance wiring to a maximum temperature of 125°C and 600 volts for sizes between 26 AWG and 9 AWG. It must pass the horizontal flame test.
  • UL 3195: UL 3195 is for internal wiring as above, but this standard only applies to 8 AWG wires.
  • UL 3196: The standard covers wire sizes from 7 AWG to 2 AWG for the same applications as above.
  • UL 3320: This includes solid or stranded conductors between 30 AWG and 2 AWG with extruded insulation for use as motor lead wire and internal appliance wiring to a maximum temperature of 90°C. The maximum continuous voltage for UL 3320 wires is 600 volts AC, but the insulation must withstand a surge of 2,500 volts and may carry a tag: "2,500 volts peak — for electronic use only."

SIS Wire Specifications

Conductor: Tinned Copper, stranded or solid
Insulation: Thermoset XLPE
Voltage Rating: 600 volts AC continuous
Temperature Rating SIS: 90°C
Dual Temperature Rating: 90°C to 125°C, depending on UL Type
Fire Rating: Many but not all types comply with the VW-1 vertical flame test
Colors: Multiple colors available
NEC Rating: SIS
CSA Rating: SIS / CL1251
UL Types: Various, including UL 3173, UL 3195, UL 3196, UL 3320
Chemical Resistance: Good
Oils and Hydraulic Fluid Resistance: Good
Sizes: 18 AWG - 4/0 AWG

Contact us at AWC for further information regarding selecting SIS wires for specific applications.