12 AWG High Temp SIS Switchboard Wire - 125°C

Parent SKU :  12SIS-3173

SKU :  12SIS-3173-500-BK

UL 3173. DESIGNED FOR INTERNAL WIRING OF CONTROL PANELS AND ELECTRICAL SWITCHGEAR.
Wire Size 12 AWG
Conductor Type Stranded
Outer Diameter 0.156 in. / 3.96 mm
Conductor Count 1
Voltage Rating 600V
Temperature Rating 125ºC

Get Product Details

Get Product Details

"The professional standard for high-density control panels—engineered with high-performance XLPE insulation and tinned copper for maximum reliability in environments up to 125°C."

Why Professionals Choose SIS Switchboard Wire

The 12 AWG SIS wire is a heavy-duty high-temperature conductor designed for precision electrical systems, fully compliant with UL 3173 standards. It is the primary choice for utility-scale switchgear, industrial control panels, and transformer leads. Our Cross-linked polyethylene (XLP) insulation is thermoset, meaning it provides superior resistance to melting or deformation even when exposed to high-thermal stress or accidental contact with soldering equipment.

  • 125°C Heat Resistance: Rated for continuous use in extreme thermal environments where standard building wire (90°C) fails.

  • Tinned Copper Conductor: Features a tin coating over the stranded copper to prevent corrosion and ensure effortless soldering and termination in high-humidity panels.

  • Chemically Cross-Linked (XLP): The insulation is chemically bonded to ensure it maintains structural integrity under extreme heat.

  • UL 3173 / CSA CL1251 Rated: Fully compliant with industrial standards for switchgear, control circuits, and internal appliance wiring.

Technical Specifications

ENGINEERING OVERVIEW: 12 AWG SIS UL 3173 600V

  • APPLICATION: Internal wiring of switchboards, control panels, and power distribution equipment.

  • VOLTAGE: Rated for 600 Volts.

  • CONDUCTORS: 65-strand soft drawn tinned coated copper per ASTM B33 and B174.

  • INSULATION: Cross-linked polyethylene (XLP), Type SIS.

  • TEMPERATURE: 125°C (257°F).

  • NOMINAL OD: 0.156 inches (3.96 mm).

Common 12 AWG SIS Applications

  • Substation Control Wiring: The preferred gauge for high-reliability connections in utility power substations.

  • Industrial Power Supplies: Wiring the internal components of large-frame DC power supplies and rectifiers.

  • Heavy-Duty Motor Leads: Providing power to industrial motors that operate in high-ambient temperature zones.

  • Automated Production Lines: Reliable wiring for the "brains" of manufacturing equipment that faces constant vibration.

  • Marine & Harsh Environments: Used in specialized marine panels where tinned copper is required to prevent salt-air corrosion.

 


Technical Note: All values are nominal and subject to industry tolerances and manufacturer corrections. Specifications are subject to change without notice. It is the buyer’s responsibility to verify that all materials meet the specific requirements of the project and comply with local electrical codes.

 



See Full Specifications

See Full Specifications

Physical Specifications

Wire Size (AWG/MCM) 12 AWG
Conductor Material Tinned Copper
Conductor Type Stranded
Strand Count 65
Outer Diameter (OD) (in/mm) 0.156 in. / 3.96 mm
Conductor Count 1
Shield Unshielded
Insulation Type XLPE
UL Listing Numbers UL 3173

Technical Specifications

Voltage Rating 600V
Submersible No
Temperature Rating 125ºC
Standards UL Type AWM Style 3173
CSA CL1251
UL Horizontal Flame Test
CSA FT2 Flame Test
Miscellaneous Information All values are nominal and subject to correction.

Usage & Installation

Primary ApplicationsSwitchboards, Control and Power Circuits, Applications up to 125° and 600 volts.
Common Uses
  • Large electrical switchgear
  • substations
  • distribution panels
  • circuit breakers
  • relays
  • contactors
  • terminal blocks
  • motor
  • coil leads
  • lighting fixtures
  • computers.

Packaging & Dimensions:

Weight per Foot 0.028 lb

Shipping and Returns

Shipping and Returns

General Shipping Information

In-stock orders placed before 3pm EST typically ship within 1-2 business days. Our business days are Monday through Friday; we do not process orders on Saturday, Sunday, or major US Holidays.

You will receive an e-mail with a tracking number within 1-2 business days from the time its shipped. You will also be able to view your order status and tracking numbers in your account order history.

Expedited Shipping

Expedited shipments are delivered Monday-Friday except on US Holidays. The order must be placed before 12pm CST to ship same day ( Mon-Fri Only).

Returns

You have 30 days from the day you receive the item to contact us for a return. Returns are subject to a 30% Restocking Fee.

Please contact us at help@wireamerica.com to request a return authorization. Have your order number or name the order was placed with ready and we will email you an RMA (return) number and instructions for return. Currently, we do not offer exchanges. A new order must be placed if you need a different item. If you provide the new order number at the time of your return request, the restocking fee may be lowered.

Orders on any items with a material value of $50 or less are non-returnable.

12 AWG High Temp SIS Switchboard Wire - 125°C

Parent SKU :  12SIS-3173

SKU :  12SIS-3173-500-BK

UL 3173. DESIGNED FOR INTERNAL WIRING OF CONTROL PANELS AND ELECTRICAL SWITCHGEAR.
In Stock
Ships in 1-2 days

Parent SKU :  12SIS-3173

SKU :  12SIS-3173-500-BK

Please select
Please select an option
$215/ea.
$430/ea.
$1,060/ea.
Please select an option
Min: 500 ft., Max: 5000 ft.
Spool (500 ft.)
$215.00
Please select an option
Maximum reached, contact us for custom orders
Contact Us
  • Fast Shipping
  • Competitive Pricing
  • Phone Support

Get Product Details

Get Product Details

"The professional standard for high-density control panels—engineered with high-performance XLPE insulation and tinned copper for maximum reliability in environments up to 125°C."

Why Professionals Choose SIS Switchboard Wire

The 12 AWG SIS wire is a heavy-duty high-temperature conductor designed for precision electrical systems, fully compliant with UL 3173 standards. It is the primary choice for utility-scale switchgear, industrial control panels, and transformer leads. Our Cross-linked polyethylene (XLP) insulation is thermoset, meaning it provides superior resistance to melting or deformation even when exposed to high-thermal stress or accidental contact with soldering equipment.

  • 125°C Heat Resistance: Rated for continuous use in extreme thermal environments where standard building wire (90°C) fails.

  • Tinned Copper Conductor: Features a tin coating over the stranded copper to prevent corrosion and ensure effortless soldering and termination in high-humidity panels.

  • Chemically Cross-Linked (XLP): The insulation is chemically bonded to ensure it maintains structural integrity under extreme heat.

  • UL 3173 / CSA CL1251 Rated: Fully compliant with industrial standards for switchgear, control circuits, and internal appliance wiring.

Technical Specifications

ENGINEERING OVERVIEW: 12 AWG SIS UL 3173 600V

  • APPLICATION: Internal wiring of switchboards, control panels, and power distribution equipment.

  • VOLTAGE: Rated for 600 Volts.

  • CONDUCTORS: 65-strand soft drawn tinned coated copper per ASTM B33 and B174.

  • INSULATION: Cross-linked polyethylene (XLP), Type SIS.

  • TEMPERATURE: 125°C (257°F).

  • NOMINAL OD: 0.156 inches (3.96 mm).

Common 12 AWG SIS Applications

  • Substation Control Wiring: The preferred gauge for high-reliability connections in utility power substations.

  • Industrial Power Supplies: Wiring the internal components of large-frame DC power supplies and rectifiers.

  • Heavy-Duty Motor Leads: Providing power to industrial motors that operate in high-ambient temperature zones.

  • Automated Production Lines: Reliable wiring for the "brains" of manufacturing equipment that faces constant vibration.

  • Marine & Harsh Environments: Used in specialized marine panels where tinned copper is required to prevent salt-air corrosion.

 


Technical Note: All values are nominal and subject to industry tolerances and manufacturer corrections. Specifications are subject to change without notice. It is the buyer’s responsibility to verify that all materials meet the specific requirements of the project and comply with local electrical codes.

 



See Full Specifications

See Full Specifications

Physical Specifications

Wire Size (AWG/MCM) 12 AWG
Conductor Material Tinned Copper
Conductor Type Stranded
Strand Count 65
Outer Diameter (OD) (in/mm) 0.156 in. / 3.96 mm
Conductor Count 1
Shield Unshielded
Insulation Type XLPE
UL Listing Numbers UL 3173

Technical Specifications

Voltage Rating 600V
Submersible No
Temperature Rating 125ºC
Standards UL Type AWM Style 3173
CSA CL1251
UL Horizontal Flame Test
CSA FT2 Flame Test
Miscellaneous Information All values are nominal and subject to correction.

Usage & Installation

Primary ApplicationsSwitchboards, Control and Power Circuits, Applications up to 125° and 600 volts.
Common Uses
  • Large electrical switchgear
  • substations
  • distribution panels
  • circuit breakers
  • relays
  • contactors
  • terminal blocks
  • motor
  • coil leads
  • lighting fixtures
  • computers.

Packaging & Dimensions:

Weight per Foot 0.028 lb

Shipping and Returns

Shipping and Returns

General Shipping Information

In-stock orders placed before 3pm EST typically ship within 1-2 business days. Our business days are Monday through Friday; we do not process orders on Saturday, Sunday, or major US Holidays.

You will receive an e-mail with a tracking number within 1-2 business days from the time its shipped. You will also be able to view your order status and tracking numbers in your account order history.

Expedited Shipping

Expedited shipments are delivered Monday-Friday except on US Holidays. The order must be placed before 12pm CST to ship same day ( Mon-Fri Only).

Returns

You have 30 days from the day you receive the item to contact us for a return. Returns are subject to a 30% Restocking Fee.

Please contact us at help@wireamerica.com to request a return authorization. Have your order number or name the order was placed with ready and we will email you an RMA (return) number and instructions for return. Currently, we do not offer exchanges. A new order must be placed if you need a different item. If you provide the new order number at the time of your return request, the restocking fee may be lowered.

Orders on any items with a material value of $50 or less are non-returnable.

Physical Specifications

Wire Size (AWG/MCM) 12 AWG
Conductor Material Tinned Copper
Conductor Type Stranded
Strand Count 65
Outer Diameter (OD) (in/mm) 0.156 in. / 3.96 mm
Conductor Count 1
Shield Unshielded
Insulation Type XLPE
UL Listing Numbers UL 3173

Technical Specifications

Voltage Rating 600V
Submersible No
Temperature Rating 125ºC
Standards UL Type AWM Style 3173
CSA CL1251
UL Horizontal Flame Test
CSA FT2 Flame Test
Miscellaneous Information All values are nominal and subject to correction.

Usage & Installation:

Primary ApplicationsSwitchboards, Control and Power Circuits, Applications up to 125° and 600 volts.
Common Uses
  • Large electrical switchgear
  • substations
  • distribution panels
  • circuit breakers
  • relays
  • contactors
  • terminal blocks
  • motor
  • coil leads
  • lighting fixtures
  • computers.

Packaging & Dimensions:

Weight per Foot 0.028 lb

Have Questions?

Call Us. Icon

Call Us.

(833) 268-8644

Email Us

SIS stands for Stranded Insulated Switchboard wire. It is a specialized industrial wire category designed specifically for the internal wiring of switchgear, control panels, and distribution boards.

SIS Switchboard wire is rated for 125°C (257°F). This makes it significantly more heat-resistant than standard THHN wire (90°C). It is specifically designed to maintain its electrical integrity in the "hot zones" inside electrical cabinets and industrial machinery.

SIS wire is the industry standard for high-performance internal wiring. Its primary applications include the internal circuitry of electrical switchgear, control panels, and distribution boards. Because of its 125°C temperature rating and resistance to oils and chemicals, it is also widely used for transformer leads, industrial motor starters, and relay logic systems in utility substations. It is the preferred choice for any environment where high-density wiring requires both flexibility and superior heat resistance.

The two main differences are heat and flexibility. SIS is rated for 125°C, while THHN is limited to 90°C. Additionally, SIS features Tinned Copper and XLP insulation, which is more flexible and "dead-soft" compared to the stiffer PVC/Nylon jacket of THHN, making SIS much easier to route in tight control clusters.

Yes. Our 12 AWG SIS wire is fully certified to UL Type AWM Style 3173, ensuring it meets rigorous safety and performance standards for switchboard and control circuit applications.

No. While both use Cross-Linked Polyethylene (XLP) insulation, this SIS is a specialized switchboard wire rated for a higher temperature of 125°C and features tinned copper for superior corrosion resistance and flexibility. XHHW-2 is a general building wire rated for 90°C and usually features bare copper. SIS is the professional choice for high-density control panels and high-heat equipment where standard building wire would fail.

Call Us. Icon

Call Us.

(833) 268-8644

Email Us