Non-Adhesive Electrical Tape: Sturdy Self-Sticking Tape for Car Wire Harnesses

Let’s look at how non-adhesive electrical tape works and the properties that make it suitable for vehicle electrical insulation.

Regular insulation tape might not cut it for wrapping electrical joints, such as after connecting car wire harnesses. 

But non-adhesive electrical tape offers the required strength, permanent bonding, and pliable properties to insulate and protect the joint. Read on to learn more.

Table of Contents

What Is Non-Adhesive Tape?

Also known as self-fusing, self-vulcanizing, or self-amalgamating tape, non-adhesive tape is a silicone-rubber tape that only sticks to itself. When wrapped around electrical joints, hoses, wires, and pipes, the tape bonds to its layers, forming a sturdy and seamless insulation that is rubbery and waterproof.

Since it is non-tacky, the tape does not leave a sticky residue when you undo it. Also, the material does not get brittle or stiff over time.

Like with other electrical tapes, this variety comes as rolls, so it must have an interleaving/barrier layer to prevent sticking before use. And it can have an iron-oxide additive to improve the silicon-rubber material’s thermal properties.

Vinyl electrical tape wrapping electric wires

Vinyl electrical tape wrapping electric wires

Non-Adhesive Electrical Tape Materials

The self-amalgamating tape usually comprises a soft silicone rubber material with low tear resistance.

So it is susceptible to abrasion and cuts. This weakness factor gets worsened by the fact that wrapping the tape requires stretching.

So while it creates a watertight seal, slicing through the layers using a sharp object is easy. But the advantage of this weak property is it makes it easy to cut the layer clean for maintenance or replacement.

A technician wrapping wire harnesses of a disassembled headlight using electrical tape

A technician wrapping wire harnesses of a disassembled headlight using electrical tape

Another non-adhesive electrical tape variant is ethylene propylene rubber (EPR), a non-vulcanizing material with reliable moisture resistance. This tape is ideal for insulating high-voltage electrical joints.

Polyisobutylene (PIB) non-adhesive tapes rank slightly lower than their ethylene-propylene counterparts because they are suitable for insulating lower-voltage electrical joints.

Other materials include butyl and ethylene propylene diene terpolymer (EPDM).

Self-Amalgamating Tape Properties

This tape has the following properties.

Self-Bonding

The non-adhesive tape has strong chemical bonds between the layers to create permanent bonds.

This bonding, cross-linking, or vulcanization occurs at the molecular level, creating a mold-like material that covers the wires, creating durable insulation.

But this bonding takes some time, which is good because it gives you room to handle the tape and layer it precisely over the work area. Usually, it takes a few minutes to bond.

So if the wrapping is imperfect, undo the layer and adjust quickly.

Insulated electrical wire joints

Insulated electrical wire joints

Also, ensure the tape has a close-fitting overlapping wrap (about a half-width overlap) to create a watertight seal.

Since the tape has no adhesive, it does not ooze when heated. Electrical insulation tape usually creates this sticky mess when installed in a hot area, but the non-adhesive type will always be clean.

Weather Proof

This tape creates a weather-proof seal that protects the covered component from moisture and engine fluids/oils. And the molecular-level bonding makes the layer tight.

Over time, the tape does not lose its adhesive properties or separate to allow the elements inside.

Heat Tested

Non-adhesive electrical tape can withstand high temperatures up to 130°C, making it ideal for insulating wire harness joints in the engine bay. And it is flame retardant.

Non-Adhesive Electrical Tape Application/Installation Considerations

Self-amalgamating tape is relatively thicker than other electrical tapes because it measures about 20 mils.

So double or triple-layering this protective layer will make the joint unappealing because it will be too thick.

On the other hand, using a few layers might compromise the bonding quality due to the reduced surface area for making contact. So try to strike a balance between the two.

Another thing to note is this non-adhesive wire harness tape is super soft, meaning it can grab or get caught by sharp items, surfaces, or corners.

So leaving the silicone-rubber material bare on the outer surface of an electrical joint is risky because you can accidentally stretch or pull it when moving the wire harness.

Therefore, you must wrap the tape using another material or separate it from other areas to keep it from sticking.

Electrical wiring repair using electrical tape

Electrical wiring repair using electrical tape

Non-Adhesive Vinyl Tape Durability and Removal

This non-sticky tape can last for decades because it can withstand extreme temperatures and does not ooze any sticky substance when exposed to heat.

Regular insulation tape usually produces this material when exposed to heat, making it lose its adhesive properties.

But the non-tacky tape type has nothing to lose. So the molecular bond will last through challenging environments.

And if you want to remove the tape, you can use a blade or box cutter to remove the non-sticky layer.

The strong bonds between the layers make it impossible to peel, so cut through to the inner layer, then remove it from the insulated surface.

But be careful not to cut or damage the component or joint under the tape.

And if cutting through to expose an electrical joint, take caution not to get an electric shock via the blade. Wear protective gloves, just in case.

Non-Adhesive Tape vs. Silicone Tape

You might confuse non-adhesive tape with silicone tape, but the two refer to different things. The former usually has PIB, butyl, EPDM, or EPR rubber.

But silicone tape features a silicone elastomer with no rubber. This structural difference brings about these properties.

Performance

Both tapes are heat resistant, but the silicone type offers better performance. It can withstand up to 260°C on the high-temperature side, while non-adhesive electrical tape can only remain stable up to 130°C.

Silicone tape is also more cold-resistant because it remains flexible and protective at up to -65°C.

When considering tensile strength, silicone tape still beats its non-adhesive counterpart because it measures 450-950 PSI against non-adhesive tape’s 150-300 PSI.

Bonding Strength

One of the most significant advantages of silicone tape is its bonding strength. It offers a higher fusibility that occurs in seconds rather than minutes. This property makes it more applicable in insulation tasks.

Color

This factor does not affect performance, but we can’t leave it out. Self-amalgamating tape is only available in black and white, but silicone tape comes in different colors.

Applications

Silicone tape is suitable for insulating or protecting surfaces in pipes or cables. But the non-adhesive or self-amalgamating type is ideal for automotive applications when insulating electrical wires and joints.

Wrap Up

Non-adhesive electrical tape is the best for covering joints in automotive wire harnesses because it has several advantages over electrical tape

The lack of an adhesive and replacing it with self-bonding gives the self-amalgamating tape type superior properties, such as durability, waterproofing, and temperature resistance. 

These factors are ideal for automotive electrical applications, so consider using the tape in your car electrical repairs. And we can recommend high-quality brands to consider.