Heat Shrink Tubing

Heat Shrink Tubing

Known as heat shrink, heat shrink wrap, heat shrink tape, wire sleeves, wire shrink wrap, etc. the miraculous material, more commonly known as heat shrink tubing, can be found in multitudes of industries as many of them need to protect important electrical components from damage. These useful little pieces of plastic can be found in railway industries, data centers, the military, and even in aerospace applications, but that doesn’t even put a dent in the vast pool of industries that this heat shrink tubing can be used in.

Heat shrink tubing is an excellent cable management tool that works alongside cable ties for any facility that needs wires visually marked and bundled together to denote their specific purpose within spaces filled with electrical components. Utilizing heat shrink tubing and cable ties enables employees to find what they need quickly and completing tasks without error, whether that relates to repairing, upgrading, or replacing electrical equipment.

There are a multitude of different materials used to create heat shrink tubing including polyolefin, polyvinyl chloride (PVC), polytetrafluorethylene (PTFE), Fluorinated ethylene propylene (FEP), polyvinyl difluoride (PVDF), elastomers, silicon, and adhesive lined heat shrink tubing, to name a few examples. Regardless of the material, these tools are excellent at prolonging the life of necessary electrical wiring and have the added bonus of being cost effective for companies to use.

What is Heat Shrink Tubing Used for?

Heat shrink tubing is used primarily to protect wiring from damage associated with the environment and provides abrasion resistance for vulnerable electrical components. For that reason, heat shrink tape can be used on several types of electrical components to ensure longevity, some of them include:

  • Stranded wire conductors which are made up of several strands of wires to allow for flexibility rather than a solid wire conductor where if bent too much and too often can break the wire. Heat shrink tubing can repair the conductor connection or connect two lines together.
  • Connectors are used when wire lines needs to be connected and disconnected from other electrical components. They are often used in circuit boards for testing before connected to the final product.
  • Terminals are essentially the end of a conductor and may also refer to an electrical connector. This is where the wires are soldered on and potentially covered with a heat shrink tube, or adhesive based heat shrink tube, to protect the exposed wire surface.
  • Power cable joints are also prime contenders for the use of heat shrink tubing as they are able to connect voltage cables together. However, it is important to make sure that the heat shrink tape is compatible with the existing insulation material.
  • Cable entry seals are easily created with the help of heat shrink tubing and they provide a watertight and fume-tight seal where cables enter enclosed spaces such as connection boxes.
  • Heat shrink tubing can also be used to repair insulation on wiring due to wear and tear from constant use.

The material that is used to make heat shrink tubing is primarily polyolefin. This is the most popular type of material used for heat shrink tubing as it is flexible, fast shrinking, durable, is highly flame retardant, is highly UV resistant, and works extremely well for chemical and electrical applications.

How to use Heat Shrink Tubing

Installing heat shrink tubing only takes a few steps to obtain the full benefits regarding wire protection. Those are:

  • Measuring the wire gauge – Remember, the insulation does not need to be removed since the heat shrink tubing is going to be secured around the entire wire, insulation and all.
  • Picking the correct shrink tubing – The final diameter of the tubing once it has been shrunk must be smaller than the wire being insulated to ensure a tight seal. This can be measured by taking the diameter of the wire and dividing it by the first number seen on the shrink ratio of the heat shrink tubing. Take for example, if the unshrunk diameter of the tubing is 0.5 inches and it has a 4:1 shrink ratio, then the final size of the tubing will become 0.125 inches or 1/8th of an inch.
  • Cutting the tubing to fit – Heat shrink tubing does shrink lengthwise a small amount, about 5-7%, so try to cut an extra ½ an inch or more to ensure the wire will be fully protected after the tubing is shrunk.
  • Positioning the tubing – Evenly space the tubing to make sure all areas needed to be covered are covered.
  • Heating the tubing – A heat gun positioned 3-6 inches from the tubing will work best for this task. Make sure to rotate the wire to evenly distribute heat for a tight seal against the wires.
  • Letting it cool down – The freshly heated tubing must be allowed to cool before putting stress on the joined wires, about five minutes will do the trick.

Gauge Sizes for Wires

The American Wire Gauge, or AWG, is one of the most frequently used wire gauge standards in the United States. It is referenced to measure the diameter of the insulated cable or wire that needs a heat shrink tube, or another type of wire marker. Determining the gauge of any wire is incredibly important regarding whether or not the marker will fit correctly and last for a long time.

To calculate the gauge of a wire if it is not specified already, the user must apply the following mathematical formula:

dn(in) = 0.005 in × 92(36-n)/39

According to the AWG standard the n gauge wire diameter dn in inches (in) is equal to 0.005 of an inch multiplied by 92 and raised to the power of 36 minus the gauge number n and divided by 39. The higher the AWG number is after this calculation denotes smaller and smaller wires diameters.

There are a couple rules of thumb regarding gauge numbers that an employee can follow, these are:

  • The AWG will decrease by three if the cross-sectional area of a wire is doubled. This subsequently causes the conductance to be doubled.
  • The AWG will decrease by six if the diameter of a wire is doubled. It quadruples the conductance and the cross-sectional area.
  • A solid round 18 AWG wire is about 1mm in diameter.
AWG #Diameter (inch)Diameter (mm)Area (kcmil)Area (mm2)
0000 (4/0)0.460011.6840211.6000107.2193
000 (3/0)0.409610.4049167.806485.0288
00 (2/0)0.36489.2658133.076567.4309
0 (1/0)0.32498.2515105.534553.4751

Choosing a Wire Marker

There are several different types of wire markers available for use in electrical component labeling. Choosing the right one for each and every facility’s unique setup is important to consider when planning for this organizational project. Some of those types of markers include:

  • Wrap around labels can be printed on any label printer and are just wrapped around the cable, it sticks to itself.
  • Wire marker tapes have words or pictograms printed on them and can simply be wrapped around the cable or wire.
  • Cable labels are oftentimes preprinted as a general label with numbers to assist in identifying cables at each end.
  • Cable stickers are often used for larger cables as they come in a variety of shapes and sizes.
  • Electric wire labels are non-flammable and non-conductive tapes that can be safely applied to any wires.
  • Cable identification tags have a thin and durable string attached to a label that can be tied onto cables.
  • Heat shrink labels are some of the best options as they are tight against the cable or wires and generally have no adhesive that can become tricky in tight spots. Some can even be printed on with a label printer.
  • UV markers involve wires and cables that are placed in dark places. These cables oftentimes will have UV ink applied to make the wiring easier to see under a black light rather than a normal flashlight.

Choosing the material for a marking strategy comes next. There are several different kinds to choose rom such as vinyl, nylon, and Teflon. Each have their own benefits in a facility’s unique setup when considering the environmental conditions that are present within the area.

Aside from choosing a type of wire marker, picking the color scheme is one of the most important aspects as maximum visibility and communication comes from the ability to visually convey a message that will enable the employee to immediately identify the type of power that the wire possesses. There are several different color schemes put forth by the National Electrical Code®, also known as the NEC®, that have been recognized by ANSI which is known known as the ANSI/NFPA 70 standard. The standard covers the basis for electrical safety in all industrial, commercial, and residential buildings.

There are three main categories that have their own color schemes within electrical safety standards. Those are:

  • DC power often requires two or three wires, the color scheme includes the following:
    • Red must be used for the positive current
    • Black must be used for the negative current
    • White or grey must be used for the ground wire if it is present
  • AC power involves different types based on the number of volts the wire will be carrying. The following color scheme involves volts at 120, 208, and 240:
    • Black must be used for Phase 1
    • Red must be used for Phase 2
    • Blue must be used for Phase 3
    • White must be used for neutral wiring
    • Green or green with a yellow stripe must be used for ground wires
  • 277/480-volt wires are high voltage connections and therefore are incredibly dangerous if not handled or labeled correctly. The color scheme for this type of power includes:
    • Brown must be used for Phase 1
    • Orange must be used for Phase 2
    • Yellow must be used for Phase 3
    • Grey must be used for neutral wires
    • Green or green with a yellow stripe must be used for ground wires

Wire Marking Sizes

When choosing a size for the wire markers, the golden rule is to make sure the label is five times the length of the wire’s outer diameter. For example, if the AWG number is 1, the outer diameter of the wire should be 7.384 millimeters, then multiply that by five which becomes 36.92 millimeters. 36.92 millimeters must be the length of the label used to mark the wire.

The length of the label, if the user is not planning to use heat shrink tubing, will help with fully protecting the wire as it is wrapped several times around to ensure a tight seal.

Creating Wire Markers

Creating wire markers is easy with the help of an industrial label printer. Having a labeling machine on-site enables the users to print wire markers on demand and up to specifications when they are needed rather than having to go to a supplier to ultimately end up putting off an important project until the wire markers arrive at the facility. Not only that but investing in an industrial label printer will save the company money in the long run since costs associated with labor and transportation need not apply if there is no supplier involved.

Durable wire markers that resist outside elements and chemicals are easy to obtain for a site that is in dire need of some better organization for their electrical equipment. The employees will appreciate the extra level of communication that these markers provide while productivity and efficiency increases as errors diminish.

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