Common Wire Specifications for PI Heaters

PI heaters, or polyimide film heaters, are widely used in applications that require stable and uniform heating. Their flexible nature and excellent heat transfer make them suitable for aerospace, medical, battery, and laboratory devices. However, one often overlooked component in their performance is the connection wire.

Choosing the right wire for a PI heater is crucial. It affects not only the heater’s reliability but also safety, temperature resistance, and long-term performance. In this article, we’ll explore the most common wire types used in PI heaters and understand how wire gauge and current capacity relate to overall heater performance.

What Types of Wires Are Commonly Used in PI Heaters?

PI heaters (polyimide heaters) require wires that can withstand high temperatures and maintain flexibility during long-term operation. Common wire types include 3132, 3122, 3135, 1332, 3239, 1571, and 1007.

Each type is designed for specific temperature ranges and applications. For instance, 3132 and 3135 are silicone wires that provide excellent insulation and flexibility. 3122 is a fiberglass wire that can endure up to 300–500°C, suitable for extreme heat conditions. 1332 uses Teflon insulation with a limit of 200°C, while 3239 and 1571 also use silicone sheaths that perform well under continuous heat exposure.

How to Select the Right Wire for PI Heaters?

Choosing the right wire depends on factors like temperature range, mechanical strength, and installation conditions. Silicone-insulated wires are ideal when flexibility and high heat tolerance are needed. For applications where the wire may contact hot metal surfaces, fiberglass insulation like 3122 offers superior thermal resistance.

If the heater operates in chemically active or oily environments, Teflon-insulated wires such as 1332 perform better due to their anti-corrosive properties. The key is balancing current capacity with thermal endurance to ensure both safety and efficiency.

Relationship Between Wire Gauge and Current Capacity

The wire gauge (AWG) determines how much current a wire can safely carry. A smaller AWG number means a thicker wire and higher current capacity. The following table lists some common specifications used in PI heaters:

Wire Gauge (AWG)	Stranding (No./mm)	Current Capacity (A)	Outer Diameter (mm)	Conductor Resistance (Ω/km)	Tensile Strength (N)
26	7/0.16	2.2	1.68	139.75	13.4
24	7/0.20	2.5	1.81	88.9	22.3
22	7/0.254	4	1.97	57.8	35.6
20	7/0.31	6	2.14	37.6	57.9
18	34/0.18	10	2.39	23.85	89
16	26/0.154	13	2.69	15.1	133.5

From the table, it’s clear that as the wire gauge number decreases, the current carrying capacity increases. For example, a 26 AWG wire carries up to 2.2 A, while a thicker 16 AWG wire can handle as much as 13 A. This relationship is crucial when designing PI heaters, as using an undersized wire can lead to excessive heat buildup, voltage drop, or even insulation failure.

Why Is Wire Gauge Important for PI Heater Performance?

Wire gauge directly impacts the electrical efficiency and heat balance of a PI heater. Using wires that are too thin may lead to voltage drops, excess heat in the cable, or even premature insulation failure. On the other hand, using overly thick wires can reduce flexibility and complicate assembly.

A well-chosen wire gauge ensures stable current delivery, uniform heating, and long product lifespan. Engineers typically match the wire size to the heater’s rated current while leaving a margin for safety.

Temperature Resistance of Common Wires

Each wire material has a different temperature range:

Wire Type	Insulation Material	Temperature Range (°C)
3132	Silicone	-60 ~ 200
3122	Fiberglass	-60 ~ 500
3135	Silicone	-60 ~ 200
1332	Teflon	-60 ~ 200
3239	Silicone	-60 ~ 250
1571	Silicone	-60 ~ 200
1007	Silicone	-60 ~ 105

From this comparison, fiberglass (3122) wires are best for extremely high temperatures, while silicone-insulated wires provide flexibility and reliable insulation for most standard heaters. Teflon wires strike a balance between temperature tolerance and chemical resistance.

How to Match Wire Size with Heater Power?

To determine the right wire size for your PI heater, use the following simple formula:

Where:

• I = Current (A)
• P = Power (W)
• V = Voltage (V)

Once you know the current, match it with the proper wire gauge from the table above.

Example:
If your PI heater has a rated power of 120 W and operates at 24 V, the current is:

From the table, a 20 AWG wire rated for 6 A would be suitable, with some margin for safety.

What Happens If the Wrong Wire Is Used in a PI Heater?

While rare in professional design, using the wrong wire can lead to overheating, insulation cracking, or poor electrical performance. The heater may fail to reach its target temperature or show uneven heating zones.

Therefore, proper wire selection is a key step in designing reliable PI heaters, especially for industrial or medical equipment where safety and precision are critical.

How Danyu Electronic Supports Custom PI Heater Design?

At Danyu Electronics, we provide custom PI heaters with tailored wire options, ensuring optimal performance for every design. Our engineering team evaluates your voltage, power, and environmental requirements to select the most suitable wire type for safe and efficient operation.

We use only certified materials that meet UL and RoHS standards, and every heater undergoes a full inspection before delivery. Whether you need small flexible heaters or large-area solutions, we can help you achieve stable heating with long service life.

FAQs

1. Why is wire selection important for PI heaters?

Because it affects safety, current carrying capacity, and thermal stability. The wrong wire can overheat or break down under load.

2. Which wire type is best for high-temperature PI heaters?

Fiberglass-insulated wire (3122) is ideal for high-temperature applications, supporting up to 500°C.

3. Are silicone wires suitable for moving or flexible heaters?

Yes. Silicone wires like 3132 and 3135 offer excellent flexibility and are perfect for movable heaters.

4. Can Teflon wires be used for PI heaters?

Absolutely. Teflon (1332) wires provide good temperature resistance and outstanding chemical durability.

5. How do I calculate the proper wire size for my PI heater?

Divide the total power (W) by voltage (V) to find current (A), then select the AWG wire that safely supports that current.

标签：wire specification for PI heater