How To Choose The Right SIS Wire

1. Understanding SIS Wire

SIS wire, short for Switchboard Internal Wire, is specifically designed for internal wiring of switchboards, panels, and control cabinets. A typical SIS wire consists of:

Solid or stranded bare copper conductor – often soft annealed for better flexibility and conductivity.

XLPE insulation (Cross-linked Polyethylene) – a high-performance thermoset insulation material.

No outer jacket – allows better heat dissipation and easier wire routing.

Flame-retardant properties – meets or exceeds VW-1 flame test standards.

Compared to conventional PVC-insulated wires, SIS control wire offers superior thermal, mechanical, and electrical performance. It is especially suitable for high-temperature, high-reliability applications in industrial settings.

2. Why Choosing the Right SIS Wire Matters

Improper wire selection in an electrical system can result in:

Overheating and fire hazards due to undersized conductors;

Excessive voltage drop, especially over long cable runs;

Incompatibility with terminals or devices (e.g., mismatched gauge like 10 SIS wire for higher loads);

Failure to meet industry standards, leading to project rejections or safety issues;

Higher maintenance costs due to faster aging or wire degradation.

Choosing a compliant and properly rated SIS control wire ensures system reliability, user safety, and successful project execution.

3. Six Key Factors to Consider When Selecting SIS Wire

3.1 Voltage Rating

Most SIS wires are rated for 600V, which suits a wide range of low-voltage control and power circuits. When choosing a voltage rating, consider:

The maximum voltage of connected equipment;

System protection requirements;

Possible voltage spikes or surges.

For example, 12 AWG SIS wire rated at 600V is commonly used in PLC control circuits and distribution panels.

3.2 Temperature Rating

Standard SIS wire is rated for 90°C continuous operation, though some variants support up to 105°C or higher. Consider:

Ambient temperature inside control enclosures;

Proximity to heat-generating equipment;

Continuous vs intermittent load cycles.

For hot environments, using high-temperature XLPE-insulated 10 SIS wire can prevent insulation failure.

3.3 Wire Gauge

The wire gauge determines current-carrying capacity (ampacity). Below is a quick reference for common SIS control wire gauges:

Also, take into account the wire length and expected voltage drop. Longer runs typically require a thicker conductor.

3.4 Insulation Type and Quality

XLPE insulation in SIS wires provides:

High heat resistance;

Excellent mechanical durability;

Chemical resistance (oil, acids, alkalis);

Reliable electrical insulation.

Choose SIS control wires with certified flame-retardant insulation that complies with UL VW-1 or equivalent standards. This ensures safety during both normal and fault conditions.

3.5 Compliance and Certification

Only use SIS wires that meet applicable industry standards. Look for:

UL 44 – Defines SIS wire requirements for insulation thickness, flame resistance, and thermal performance;

CSA certification – Ensures Canadian safety compliance;

RoHS – Confirms absence of lead and other hazardous substances.

Always verify UL E-number markings on the wire jacket to ensure authenticity. Certified 12 AWG SIS wire or 10 SIS wire is a must for commercial and industrial applications.

3.6 Application-Specific Requirements

Different environments may demand special characteristics in SIS wire:

Oil and chemical resistance;

Flexibility (especially for dynamic installations);

UV resistance for outdoor use;

Compatibility with terminals and connectors.

For example, standard 14 SIS wire might be fine for indoor static use, but outdoor installations may require UV-rated SIS control wire.

4. Typical Applications of SIS Wire

4.1 Switchboards and Distribution Panels

SIS wire is widely used for internal wiring in:

Switchgear and panelboards;

Circuit breaker interconnections;

Busbar and terminal connections.

12 AWG SIS wire and 14 SIS wire are often preferred due to their balance between size, flexibility, and current rating.

4.2 Industrial Control Systems

In factory automation, SIS wires are ideal for:

Motor starters and contactors;

Control signal wiring;

Interfacing PLCs and I/O devices.

Their flame-retardant insulation and consistent performance make them ideal for high-density control cabinets. 10 SIS wire is often chosen for power-heavy actuators and drive systems.

4.3 Commercial Building Wiring

SIS wires are also common in:

Smart building control systems;

Fire alarm and monitoring circuits;

UPS internal wiring.

The flame resistance and certification of SIS control wire ensure building codes are met, especially in public or high-traffic spaces.

5. Tips for Purchasing and Installing SIS Wire

5.1 Procurement Advice

Choose reliable manufacturers with UL and CSA listings;

Prioritize vendors with fast delivery and inventory availability;

Compare pricing among different sizes like 12 AWG SIS wire and 10 SIS wire to optimize cost-to-performance ratio;

Inspect wire for proper labeling and quality control marks.

5.2 Storage and Handling

Keep wire spools in dry, ventilated storage;

Avoid mechanical damage or crushing;

Label spools clearly by size (e.g., "14 SIS wire – Blue").

5.3 Installation Guidelines

Strip insulation carefully without damaging copper strands;

Follow minimum bend radius specifications;

Use proper lugs or terminals with crimp tools;

Bundle and route wires cleanly inside panels.

For dense control systems, color-coded SIS control wires (red for power, blue for neutral, etc.) help with troubleshooting and maintenance.

Dongguan Greater Wire & Cable Co., Ltd. is deep presence in the American market has made us not only an exporter, but also a technical partner for our customers. We are familiar with cable design, performance matching and transportation requirements to ensure smooth project progress. If you are looking for a stable, professional and flexible supplier, please choose Greater Wire. Welcome to contact us to start an efficient cooperation journey.