I have recently been upgrading my garage and had to repair and move some electrical sockets, I always have some electrical insulation tape lurking at the bottom of my tool kit to use for jobs like this.
It’s great to cover cables temporarily whilst they are waiting to be reconnected, I also found some old heat shrink which does a similar job only it is heated up rather than sticky and this made me wonder if electrical insulation tape behaves the same when hot
I did a little research and asked the question: does electrical tape melt when it gets hot? Here’s what I found out,
When heated electrical insulation tape will melt and deform. Industry safety standards such as BS 4J10:1991 require that electrical tape should be non-flammable and safe to use in temperatures up to 176℉ (80℃). The adhesive properties are reduced in temperatures over 180℉ (82℃).
After digging a bit further I discovered some interesting facts about Electrical insulation tape and how it reacts to heat.
It is designed to be used in all sorts of conditions both internal and external and has some great mechanical properties including electrical insulation, abrasion, and heat resistance. Let’s take a look at it in more detail.
What is Electrical insulating tape made from?
Electrical insulation tape is made from pressure-sensitive plastic vinyl, and the typical construction of electrical tape uses a Polyvinyl Chloride (PVC) backing strip and a strong rubber adhesive coating.
PVC is one of the most commonly used thermoplastics in the world with around 40 million tonnes being produced per year for various uses worldwide. PVC was first created in 1872 by a German chemist called Eugen Baumann. You can find out more about PVC from CM
The PVC backing used in electrical insulation tape is usually modified with a chemical plasticizer such as diisononyl phthalate or DINP. This allows the tape to be flexible so that it won’t break easily, making it perfect for wrapping around cables and connectors and other electrical components.
This vinyl backing material is then coated on the reverse side with a rubber adhesive to enable adhesion to most materials including itself, making the tape very useful in a number of applications.
The rubber resin which is applied to the underside of the electrical tape allows high levels of mechanical protection, good sealing capability offering moisture protection and the PVC backing material provides high levels of electrical insulation.
What temperature does Electrical melt?
Vinyl electrical tape is designed to be heat resistant and is required to be nonflammable and withstand temperatures of up to 176℉ (80℃) which complies with industry standards like BS 4J10:1991 and BS EN 60454 Type 2, which relates to fire safety. The HSE has some great information, guidelines, and electrical standards which you can find here.
Most commercially available electrical tape is designed to work in a wide range of temperatures and manufacturers like 3M state that their Scotch® Super 33+™ Professional Grade Vinyl Electrical Tape, which was originally launched in 1985, will give high performance both mechanically and electrically between temperatures of 0°F (-18°C) and 221°F (105°C).
To meet the requirements of industry standards electrical tape is designed to be non-flammable and is often self-extinguishing, this means that it won’t burn but rather melt and deform when heated to temperatures above 176℉ (80℃).
Although electrical insulation tape can withstand a wide range of temperatures. When used above 176℉ (80℃) and the mechanical and thermal properties of the PVC tape and the adhesive start to become compromised.
Melting temperatures for PVC range from 212 °F (100 °C) all the way up to to 500 °F (260 °C), the actual melting point will be dependent upon the type and volume of additives used to manufacture the PVC.
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Is PVC electrical Insulation tape toxic when heated?
As with lots of plastic synthesized materials, PVC electrical tape will give off fumes when exposed to high temperatures, naked or direct flame.
The fumes emitted when PVC tape is heated include hydrogen chloride (HCl), which is highly toxic and should be avoided.
PVC electrical tape tends to melt and deform relatively quickly rather than to burn, when at high temperatures, as it won’t actually catch fire it can be misleading as this melting process will still give off toxic fumes.
Where high temperatures are expected or there is a risk of exposure to flame the use of PVC-free insulation should be considered.
What are the Advantages of PVC tape?
- PVC is readily available and relatively inexpensive.
- PVC is dense and making is hard and can resist impact deformation well.
- PVC has very good tensile strength.
- PVC tape is very resistant to chemicals, alkalies, and acids
- PVC tape has excellent resistance to abrasion
- PVC tape has good resistance to moisture and corrosion
- PVC tape can be used in varying weather conditions (including ultraviolet exposure)
What are the Disadvantages of PVC Tape?
- PVC has poor heat stability. Therefore chemical additives are used to stabilize the material at higher temperatures.
- PVC emits toxic fumes when melted or subject to a fire.
Although there are some shortcomings, PVC is a versatile material overall. With a unique set of qualities that make it particularly useful for all sorts of commercial use. It is widely used in the construction business, for more information why not check out our beginner’s guide to electrical insulation tape and look out for more posts on the uses of PVC coming soon.