What Is The Difference Between SPT-1 Wire And SPT-1W Wire

Many customers have questions when purchasing our SPT-1 wires: what is the difference between  SPT-1 wire and SPT-1W wire? They look very similar, with the same conductor specifications and wire diameter for the same wire number. So what is the difference?

First, it is necessary to clarify the basic definition and common characteristics of the two wires.

Both UL SPT-1 wire and UL SPT-1W wire belong to parallel flexible LAMP CORD, which are composed of two parallel stranded copper conductors and PVC insulation layers. This structural design makes them have good flexibility, easy to bend and arrange during installation, and the parallel conductors can be quickly separated (also known as "zip cord") when needed, which improves the convenience of use. In terms of core electrical parameters, the two wires have the same rated voltage of 300V and rated temperature of 60℃, and the conductor specifications are both 18-20 AWG stranded bare copper or tinned copper. The insulation thickness is uniformly 0.76mm, and the maximum conductor DC resistance at 20℃ is consistent (for 18AWG conductors, the maximum resistance is about 23.2Ω/km). These common characteristics determine that the two wires have the same basic electrical performance and can carry the same current load under the same use length—for example, they can carry 10 amps within 0-50 feet, 7 amps within 51-150 feet, and 5 amps when exceeding 150 feet, which meets the power supply needs of most small household appliances such as lamps, clocks, and small fans.

The fundamental difference between UL SPT-1 WIRE and UL SPT-1W WIRE lies in their environmental adaptability, especially the low-temperature resistance performance.

This difference is directly reflected in the temperature range of their safe operation. According to UL standard test data, the operating temperature range of UL SPT-1 wire is -20℃ to 60℃, which is suitable for general indoor environments with relatively stable temperature. In contrast, UL SPT-1W wire has a wider operating temperature range of -40℃ to 60℃, which means it can maintain stable performance even in extremely low-temperature environments. This difference in low-temperature resistance is not caused by changes in conductor materials or insulation thickness, but by the formula optimization of the PVC insulation material. The insulation material of UL SPT-1W wire adds special low-temperature resistant additives, which improves the flexibility and crack resistance of the insulation layer at low temperatures, avoiding the problem of insulation brittle cracking and leakage risk caused by low-temperature hardening of UL SPT-1 wire in cold environments.

The difference in low-temperature resistance further defines the clear boundary between the application scenarios of the two wires. UL SPT-1 wire, as a standard type of lamp cord, is mainly used in indoor environments with mild temperature conditions. Typical application scenarios include power supply connections for indoor table lamps, floor lamps, desk clocks, radios, and other small household appliances. In these scenarios, the ambient temperature rarely falls below 0℃, and UL SPT-1 wire can fully meet the safety and stability requirements. In addition, due to its mature production process and standard material formula, UL SPT-1 wire has a relatively low cost and is the preferred choice for general indoor electrical connection projects that do not have special low-temperature requirements.

UL SPT-1W wire, on the other hand, is targeted at application scenarios that involve low-temperature environments, especially outdoor or semi-outdoor low-temperature occasions. For example, in outdoor lighting systems in cold regions (such as courtyard lamps, street lamps in cold northern areas), power supply connections for outdoor portable electrical equipment (such as outdoor heaters, temporary lighting for construction sites in winter), and electrical connections in refrigeration equipment auxiliary systems (such as power cords for small refrigeration accessories). In these scenarios, the ambient temperature may drop to -20℃ to -40℃ for a long time. If UL SPT-1 wire is used, the insulation layer is likely to become brittle and crack, leading to short circuits and other safety hazards. UL SPT-1W wire, with its optimized low-temperature

In short, both SPT-1W and SPT-1 are suitable for AC power supplies and are seasonal products. SPT-1 is generally used indoors, while SPT-1W is suitable for outdoor use. "W" indicates weather resistance, sunlight resistance, and superior low-temperature performance.

Guangdong Zhengfeng Wire&Cable, as a professional cable manufacturer, deeply understands the importance of these subtle differences to the performance and safety of end products.

The company's UL SPT-1 wire and UL SPT-1W wire series products strictly adhere to UL international standards. From conductor selection and insulation extrusion to finished product testing, every step is meticulously executed to ensure stable and reliable product quality.

Zhengfeng Wire not only mass-produces these standard-compliant general-purpose products but also leverages its deep technological expertise to provide customers with customized cable application solutions.ire&Cable

Our products, with their superior quality assurance, have been exported to many countries and regions worldwide and are widely used in lighting manufacturing, home appliance components, and holiday decorations. Furthermore, efficient delivery times and attentive service have made them a trusted partner for numerous domestic and international brand clients.

If you have any further questions about electrical wires, feel free to contact the Zhengfeng Wire&Cable team. We'd be happy to share our knowledge with you.