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Spool Insulator

The spool insulator is also called shackled insulator. They are a type of insulators used on low voltage power lines. They provide insulation for the conductors on the pole.

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         Spool insulators are components of a distribution line that provide insulation on both of the primary and secondary conductors. They are also known as shackle insulators or shackle type insulator. It has a grove on the outside which makes it easy to install wires and a hole at the center which provides a platform for mounting.

    Types of Spool Insulators

    The types of spool insulators are categorized into two according to the material they are made from. These are porcelain spool insulators and ceramic spool insulators.

    Porcelain Spool Insulators

    These are suitable for overhead transmission and distribution lines. They are braced on tension rod or angle pole to support the conductors with insulation.

    Ceramic Spool Insulators

    Ceramic spool insulators are used in line with the ceramic suspension insulator.

    Advantages of the Materials Used

    • Porcelain and ceramics are strong and durable as the can only be distorted when subjected to extreme physical force.
    • Porcelain and ceramic have high thermal strength and resistance thus making them less affected by high temperatures.
    • Ceramic and porcelain materials have high resistance to surface degradation.
    • Both ceramic and porcelain materials are not likely to corrode unless exerted to extreme measures to destroy them. They are varnished to protect them from caprice of nature.

    Application of Spool Insulators

    • Spool insulators can be used in both vertical and horizontal positions.
    • They are used in overhead lines with low voltages.
    • They are used in distribution systems by arranging them in between towers and conductors to support and insulate.
    • They are also used with a bolt placed on them to avoid current from flowing from the conductors.

    Advantages of Spool Insulators

    • Spool insulators are highly steadfast for conductors.
    • They are designed to assemble the demands of electricity.
    • Spool insulators are the most convenient for maintaining protection in different electrical appliances.
    • Spool insulators withstand a high amount of current and temperature.

    The only disadvantage of spool insulators is that they apply to low voltage distribution networks only.

    Fittings used with Spool Insulators

    Splicing Fittings

    These are used in repairing or splicing conductors and ground wires of overhead transmission lines

    Guy Wire Fittings

    These are designed to add steadiness to the supported structures.

    Protection Fittings

    These are used to prevent vibrations of the conductors and the ground wires for overhead lines.

    Link Fittings

    Link fittings are used to connect clamps to insulators or insulators and wire clamp to tower arms and substation structures.

    Strain Clamp

    Strain insulators are used to connect conductors and ground wires to insulators or to link fittings to tower arms and substation structures.

    Suspension Clamp

    These are used to hold the conductors and wires to the pole or tower.

    Factors to Consider when Buying Spool Insulators

    Material used to make the insulator is important as it should have high resistance to extreme temperatures.  It should also be strong and durable to be able to last long with minimal maintenance.

    Cost of the insulator should also be considered as it should be affordable depending on the material used.

    Design of the insulator should be able to accommodate the intended use of the spool insulator. It should have a hole at the center and a groove on the outside to be able to mount the conductors.

    Insulator failure should also be considered as the transmission line has to continue to function regardless of the failure of one insulator.

    Insulator selection should be considered as one should select according to the purpose intended for the insulator. Different materials are used to make the insulators should be able to add the effectiveness of the insulator.

    Frequently Asked Questions

    QWhat is a spool insulator?

    A. A spool insulator is a component used to provide insulation for both the primary and secondary conductors on a distribution line.

    Q. What are the materials used for spool insulators?

    A. Spool insulators are mainly made from porcelain and ceramic.

    Q. Where are spool insulators mainly found?

    A. Spool insulators are mainly found on the racks in an overhead distribution line.

    Q. Which fittings are used with spool insulators?

                    A. Spool insulators are used with other fittings such as guy wire fittings, protective fittings, splicing fittings and link fittings.