Electrical Tape. Can it catch fire? Is it Safe?

1) What is Electrical Tape?

Electrical tape is a type of tape used by electricians and engineers where electrical systems are concerned. Whilst it is often not acceptable to tape wires together, electrical tape does have its uses and can provide an additional layer of protection (in some instances) beyond the single insulation of cables and wiring. 

Electrical Tape has various uses for electricians carrying out their day to day works and I can tell you from experience that electricians use electrical tape for various applications other than its intended electrical use.

2) How is Electrical Tape Made?

Electrical tape is generally made with a PVC backing and some form of rubber adhesive. The PVC backing is responsible for the tapes ability to stretch, conform and flexibly conform to the contours of electrical wires. The adhesive allows the tape to have varying degrees of adhesion to different surfaces. The tape is formed from extremely thin layers of PVC, adhesive combined and the wound onto a long drum. The drum is very wide and contains a cardboard core. The tape is wound around this core in widths around a metre wide or more. When the drum reaches the desired thickness, the winding process is stopped. The drum is then spun and a blade cuts the tape into the desired widths forming individual rolls of electrical tape.

3) What are the Temperature Ratings of Electrical Tape?

There are many varieties of electrical tape on the market across the world. Each type of tape has a different intended purpose and various applications. There are self-extinguishing tapes which are designed to be heat resistant and to avoid catching fire, tapes that are intended to offer a layer of insulation to the cable on which they are installed and generic tapes that have various applications.

Below are some common tapes from a couple of companies. Each has different purposes, temperature ratings and varying costs.

RS Products

RS pro Insulating Tape Service Temperature -5°C to +70°C

Rs pro AT4004 class B 130°C Polyester Tape Service Temperature 0°C to +130°C 

3M™Products

3M™ PTFE Film Electrical Tape 60 can withstand a temperature range of 32 to 356 °F (0 to 180 °C).

3M™ Scotch ™ Vinyl Electrical Tape Super 33 can withstand a temperature range of 0 to 220 °F (-18°C to 105 °C).

3M™ TEMFLEX™ Vinyl Electrical Tape can withstand temperatures up to 60°C.

3M™ Scotch® Rubber Splicing Tape 23 can withstand temperatures up to 90°C 

4) Can Electrical Tape Catch Fire?

Some types of electrical tape can indeed catch fire. Whilst manufacturers will ensure that their electrical tapes are able to resistance most normal maximum circuit operating temperatures, not every electrical tape product is manufactured and designed to be fire resistant or to self-extinguish in the event of overheating or combustion.

The cheaper, more generic tapes intended for Standard C22.2 No.197-M1983 “PVC Insulating Tape,”everyday and DIY use are less likely to have fire resistant properties. Where fire resistant properties are required from an electrical tape, care should be taken to select the correct product and thoroughly check the specifications to ensure that the product meets the needs of the particular installation conditions.

5) Flammability Standards and Ratings for Electrical Tape

Across the world, there are different standards of manufacture for electrical tapes and conditions must be met by manufacturers to ensure that their products meet the requirements set out. Each set of standards will take into account the voltage of the operating systems, the typical installation conditions and other factors that affect the tapes performance.

American Standards​

PVC tape is evaluated to ANSI/CAN/UL 510 for the United States. ANSI/CAN/UL 510 

Canadian Standards

Standard C22.2 No.197-M1983 - PVC Insulating Tape 

British Standards 

Pressure sensitive tapes for electrical purposes BS EN 60454-2 :2007 Formally BS 3924.

6) Alternatives to Electrical Tape for High-Temperature Applications

Where electrical connections need to be made, there are alternatives to using electrical tape in some instances. 

6.1) Junction Box

Where possible a junction box can be used to contain electrical connections safely. A junction box should be available for inspection and maintenance of electrical connections in most instances. Exceptions apply where a junction box is classed as "maintenance free". 

A junction box will typically have an outer casing preventing contact with single insulated cables and contain some form of making connections safely such as screw terminals, clamp type terminals or crimps. 

6.2) Crimping Cables

A suitable crimping tool and crimp connectors can be used to connect wiring together. The single insulation of the wiring should then be covered with some form of protection to prevent damage, water ingress or other external influences from affecting wiring and connections. One way of achieving this can be heat shrink tubing. 

6.3) Heat shrink tubing

​Heat shrink tubing is an alternative to electrical tape when the need for covering single insulation on cables arises. The tubing is slipped over the wire before the final connections are made. Once the wiring has been connected, the heat shrink tubing is slid into place and, using a heat gun, the tubing is shrunk over the connection forming a seal and offering some protection. 

6.4) High Temperature Terminal Blocks

Where high temperatures are a problem it is often recommended to use high temperature terminal blocks. These blocks are designed to keep electrical connections safe from external high temperatures.

7) Common Misuses of Electrical Tape and Associated Dangers

Electrical tape can be used for temporary emergency repairs but should not be used to:

7.1) Make permanent connections with wiring

​Permanent connections in electrical wiring need to be made with a mechanically sound joint that can survive the operating temperatures, frequency vibrations and expansion and contraction changes under normal operation of the circuit. 

Taping wires together is generally not a good idea!

7.2) Dangers​ 

Loose connections can easily cause fires, tape can come loose over time, lose its adhesive and fall off resulting in access to live parts.

7.3) Reattach a fuse box or consumer unit cover long term

Whilst a broken consumer unit or fuse box cover is dangerous, re-securing with electrical insulation tape should only be considered a temporary solution. No matter the different types of tape, securing a consumer unit or electrical panel cover with tape can lead to a false sense of security and could be a fire hazard. Gaffer tape or masking tape is also not a solution to a broken cover. A new cover should be sought for replacement or, if the unit is particularly old, a replacement unit should be considered. 

7.4) Dangers

​The adhesive properties of electrical tape are not sufficient for securing a cover over live parts in this manner. There are many uses of electrical tape but resecuring a fuse box or electrical panel are not one of these uses!

7.5) Prevent access to live parts on consumer unit fronts instead of blanking plates

​There are many consumer units, fuse boxes and electrical panels that I have encountered during my time as an electrician. No matter the type of electrical tape, using it to prevent access to live parts across the front cover of the consumer unit is not a good idea. The right type of tape for this particular problem is NO TAPE. Special blanks should be procured and installed to prevent access to live parts. 

7.6) Dangers

​Even a good electrical tape will still allow a sharp object, finger, or other foreign body to enter the consumer unit or panel. Tape can lose its adhesive properties and fall off resulting in access to live parts once again.

8) Electrical Tape vs. Other Types of Insulating Tape

The most suitable type of tape for use in electrical systems is electrical tape. A good quality roll of electrical tape is an essential part of an electrician’s stock or tool kit. Masking tape, gaffer tape, duct tape and other forms of tape are potentially dangerous when used with electrical systems. They will contain neither the insulative properties required to prevent electrical shock from high voltage or self-extinguishing properties to prevent fire during short circuits, extreme temperatures or electrical circuit adverse conditions. 

Only heat-resistant tapes designed for electrical applications should be used on electronic devices and for general electrical work. A better choice would be heat-shrink tubing or other jointing and protection methods discussed above. 

9) What to do if Electrical Tape Overheats or Melts

The heat resistance of electrical tape can only cope with a limited level of high temperatures dependent upon the electrical insulating tape used. Where electrical tape melt situation occurs, the electrical circuit should be safely isolated and a better insulation method found for the situation. The only appropriate choice where tape has melted is to examine the reasons why. 

If you find that you have an electrical problem where tape has failed, overheated, or caught fire, then you must call an electrician to attend and check for issues.

10) ​When is Electrical Tape useful?

​Aside from the widespread use of electrical tape in wiring systems, there are a few uses that electricians will have for these types of adhesive tapes. 

• Taping wires to rods to fish cables through voids and cavities.
• To attach tricky screws to a screwdriver when installing ceiling lights alone.
• To mark electrical accessories when fault finding.
• As a temporary plaster or band aid (I'm not saying its sanitary!!).
• To mark tools in a tool bag for easier identification.
• Wrapping around cables for identification.
• To mark legs of a ring final circuit for easier testing (UK RING FINAL CIRCUITS)

11) ​Conclusion

​Whilst electrical tape can indeed catch fire under the right conditions, most tapes are relatively heat resistant and designed to withstand the operating temperatures of electrical circuits. There is no substitution for proper electrical connections, electrical junctions, and electrical wire safety coverings. Consideration should be given in each situation regarding the best ways of solving the electrical problem and electrical tape may not always be the best choice despite its low price and ready availability.