What are the benefits and uses of double insulated wire?

If you are planning to lay cables that will last for a long time, then you will need double insulated wire. In some cases ordinary single layer insulation may not be sufficient and there is a risk of short circuits or electric shocks. However, double insulation wires offer extra protection to insure safety and durability.

Most people who are inexperienced with cables often wonder: what is the difference between a double insulated wire and a single layer? In our latest blog post, we’re going to dig deep into the benefits of double-insulated wires and how it differs from single-layer.

What is double insulated wire?

Double or reinforced insulation cable can be an effective means of preventing the risk of electric shock. The method takes two main forms: firstly, it involves applying a higher level of insulation to the basic insulation layer, which can be achieved by adding insulators or transformers. Secondly, a reinforced layer of stronger, more resistant insulation is applied directly to energized components or assemblies that are susceptible to electric shock.

Through the double protection mechanism, it secures that no electric shock will occur even under extreme conditions, thus guaranteeing the safety of people and equipment.

what does double insulated wire look like

Visually, double insulated wire colours mostly are available in brown and blue.

double insulated wire

Cable Construction

The insulating layer features a double-layer structure comprising an inner and an outer layer.

  • The inner layer is made of low-smoke halogen-free crosslinked polyethylene insulation.
  • The outer layer consists of a low-smoke, non-halogen resistant material.

What is the difference between single and double insulated wire?

Double insulated wires utilize two or more layers of insulation. It provides greater resistance to penetration than single-layer cables and is more reliable and durable in complex environments.

single insulated wire

In contrast, single-layer pvc cables omit the extra layers of insulation. As a result, it may be slightly inferior in terms of mechanical properties, but it is simpler to construct, cheaper to produce and easier to maintain.

Benefits of double insulated wires

Double insulated wires play a key role in many fields due to their excellent performance. The following are the main advantages, demonstrating their efficient and safe use:

1.High operating temperature:

Double insulated wires can withstand extreme temperature ranges of up to 90°C to 250°C. This characteristic makes it advantageous for applications in high-temperature environments. Such as nuclear power plants and other high-voltage, high-power environments.

2. Fire resistance:

Considering the seriousness of electrical fires, the design of double insulated wires takes full account of fire resistance requirements. Low-smoke, halogen-free flame retardant materials can effectively prevent fires from occurring.

3. Longer life:

The special construction and material selection of double insulated copper wires achieves higher mechanical strength and electrical properties, extending the service life of the cables. The overall maintenance and upgrading of the power system provides a longer period of time.

4. Explosion protection:

Even in the event of an emergency start-up or fault condition, the highly compacted insulating material in mineral insulated cables prevents the passage of vapors, gases and flames between the equipment parts connected to the cable.

5. Secure and leak-proof:

Wires may be frequently abraded under the influence of the external environment. The use of double insulated wires reinforces the wire and prevents damage caused by friction. It prevents leakage and keeps the safety of electricity.

Now we’ve covered the advantages, let’s dive into a practical application example:

Application of single core double insulated cable

Double insulated wires are mainly used to connect large power systems to assure efficient transmission of electrical energy. The type of cable is suitable for applications where high voltages and currents need to be withstood. We can usually find it more common from the following occasions:

Power connections between internal building structures: In these situations, single core double insulated wire needs to provide a mechanically robust connection while being able to withstand voltages ranging from 450 to 750 volts.

Distribution nodes: In industrial and commercial buildings, distribution nodes often use double-insulated cables to make certain the reliability of the power supply.

Lighting circuits: Lighting systems often require high-capacity power supplies, so double-insulated cables may also be used.

Heavy motors: Double insulated wires are ideal for some heavy mechanical equipment, such as excavators or cranes, which require a higher level of cable protection.

Vibrating equipment: Although not as common, there are cases where double insulated wires can also be used to connect highly vibrating equipment, such as wind turbines or generators.

Plus, double insulation speaker wire also can used in audio systems. Incidentally, fewer motor and vibration equipment housings support the type of cable. It may be due to the fact that solid conductors are designed as high tensile conductors, but fatigue quickly in high vibration applications.

How does double insulation work?

The double insulation technique is an effective method of protection against electric shock. It involves providing double protection by applying two layers of insulation to the equipment.  Two layers of insulation are the “basic insulation” and the “additional insulation”.

About “double insulated meaning:

  • The basic insulation is located between the energized part and the inaccessible conductor, and it provides the basic protection for the normal operation of the equipment.
  • When the basic insulation fails, its protective capacity will be affected, at this time, additional insulation (also known as protective insulation) began to play a role. The extra insulation prevents the human body from being electrocuted while also preventing electrical components from malfunctioning due to contact with inaccessible conductors.


Double insulated wire achieves efficient protection of electrical equipment by constructing two layers of insulation on the equipment with different but complementary functions. The basic insulation provides the most fundamental protection, while the additional insulation builds on this to further enhance safety. When designing and applying a double insulation system, it is integral to consider the specific needs of the equipment, its structural constraints as well as the actual operating conditions.

For double insulated cable specifications or double insulated wire for sale, please feel free to consult ZW cable


Is armoured cable double insulated?

Definitively, steel wire armored (SWA) cables are considered to have reinforced insulation. The cable type is also very durable. It shows excellent performance in a variety of harsh environments.

Which wire is not required in double insulation?

Grounding Wire. Double insulation is a method of guaranteeing safety by providing two layers of insulation between electrical components and any parts accessible to the user. The use of a grounding wire is not required because the additional insulation is sufficient to prevent any contact with energized parts.

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About Me
Richard Zi
Richard Zi

My name is Richard Zi, and serve as the General Manager of ZW Cable. With a deep and extensive background of more than 15 years in the cable industry, I am excited to share my wealth of knowledge and experience.ZW Cable is a renowned company in the field of cable manufacturing in world, we specialize in selecting the best cable sizes and effectively solving all your cable challenges. If you have any questions or needs regarding cable solutions, please contact me and I assure you of the highest standards of personalized and effective guidance and support.View All My Posts >>

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