Sometimes, using one tool in the place of another can make sense, but that’s not often the case when performing any type of electrical work. You might want to use duct tape when you’re out of the waterproof electrical tape you generally use, but you probably shouldn’t. I’ve worked on many wiring tasks through the years when working on DIY projects, and while using different tools can make sense, more often than not, it’s better to be safe than sorry. That being said, never use duct tape when you need to use electrical tape. Tape used in electrical applications needs to be highly adhesive, resistant to corrosion, be flame resistant and capable of withstanding up to 600 volts. And last but not least, it should protect against the elements, and insulate against them well.

But let’s say you absolutely have to use duct tape instead of waterproof electrical tape. What will happen? What are the differences between electrical and duct tape? Well, simply put, duct tape is designed to adhere to a wide range of materials. It can stick on almost anything, from brick to wood. Electrical tape, on the other hand, is specifically designed to stretch and stick to itself, which if you’ve used it, you’ll probably know what happens when you lose control trying to cut it. It will stick quite well to insulated wiring, which is its main purpose. Here are the main differences between duct and electrical tape.

Colours

Duct tape is available in virtually any colour. I’ve personally used many different types of colours to label moving boxes when moving, and it was super helpful. However, the colours of duct tape are purely cosmetic, not functional. On the other hand, electrical tape is generally black. If you can find other colours, know that they typically correspond to traditional wire colours – green is ground, white is neutral, and so on.

Materials

Duct tape is typically made of thin polyethylene-coated cloth with fibres that make it easy to tear without using too much strength, while electrical tape is made of PVC or stretchy vinyl. 

Heat and Moisture Resistance

Although duct tape is strong initially, it can degrade rather quickly, especially if exposed to heat or water. Electrical tape, on the other hand, doesn’t have this problem. It’s incredibly durable and can withstand exposure to both heat and water. Some electrical tapes are completely waterproof, while others are just resistant. Waterproof electrical tape is even more durable and it’s estimated to have a shelf life of about 5 years, even when used in extreme conditions. However, its lifespan can vary. Generally, you’ll know it’s not good anymore if it appears too gummy or brittle.

Strength

This is probably the only characteristic that duct tape excels at. The fibres that are integrated into duct tape make it quite strong, but that’s generally not a concern when performing electrical work anyway. Electrical tape doesn’t require the tensile strength, since its main job is to insulate rather than adhere.

Price

Electrical tape is available in budget and professional-grade options. Either way, it’s typically more affordable than duct tape. The price of the tape will come down to the brand. You almost always want to go with tape that’s from a well-known brand, just to have peace of mind. Plus, it won’t break your bank.

How to Use Electrical Tape

Electrical tape should be used in combination with other electrical-specific fasteners. It’s ideal for providing an extra layer of protection, but it shouldn’t be used to hold in wires into a wire nut. The wire nut should be the one doing all the holding. If it doesn’t hold, you probably need a wire nut of a different size, as it should grab on securely. You can think of electrical tape as a temporary patch. it’s a suitable band-aid, but it shouldn’t be used for major repairs, as it simply isn’t enough. Also, don’t use it to make permanent connections between two wires, like a junction box and light switch.
When using it, start by testing the wire cap, then checking for a strong grip on the stripped wires, before wrapping the wires together by slightly overlapping the tape. Personally, I keep a medium-strong pull on the electrical tape at all times to ensure a tight wrap.

Do You Have to Use Wire Nuts?

Wire nuts are considered essential, not just from a safety standpoint, but also from a regulations code standpoint. You should never twist two wires together and just cover them with electrical tape – you must use wire nuts. Additionally, if your work gets inspected, you’ll probably fail if your connections are made using just electrical tape.

Can Electrical Tape Catch Fire?

Anything can catch fire at the right temperatures, including electrical tape. Most electrical tape can handle up to 80°C. Almost all home electrical applications won’t reach those temperatures, but make sure you use tape from reputable brands.