SIS Wire

Additional Information

What is SIS Wire?

The meaning of 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.

What are the Intended Applications of SIS Wire?

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."

How is SIS Wire Constructed?

SIS wire features a single conductor with tinned copper that can be either solid or stranded, ranging from 18 AWG to 4/0 AWG. For wires between 18 AWG and 12 AWG, both solid and stranded options are available, with larger sizes exclusively stranded. The insulation is made of XLPE, a thermoset material known for its durability, moisture resistance, chemical and oil resistance, and natural fire resistance, with most SIS wires carrying WV-1 fire certification.  

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."

Does Allied Wire & Cable carry other SIS Wire brands?

Allied Wire & Cable carries SIS Wire from Belden Cable as Belden SIS Hook Up Wire.

SIS Wire Specifications

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