How to Choose and Install Electrical Insulators Correctly: A Guide to Avoiding the Most Common Mistakes

February 20, 2024

Electrical insulators are critical components for the protection and proper functioning of any electrical system. Wrong choice or improper installation can compromise their effectiveness and cause risks of short circuits, electric shocks, overheating and fires. Let’s see what are the most common mistakes to avoid when selecting and installing electrical insulators.

electrical insulators
Close up circuit breakers and wire in control panel.

Choosing electrical Insulators Not Suitable for the Intended Use

There are many types of electrical insulators, which differ in characteristics like dielectric strength, thermal resistance, mechanical strength, water absorption and so on. It is therefore essential to choose the insulating material best suited for the intended use, making sure it is adequate for operating voltages, temperatures and other expected conditions. For example, low water absorption materials are required for insulation in damp or outdoor environments.

Incorrect Sizing of Thicknesses

The thickness of an insulator determines its dielectric strength, i.e. its ability to withstand voltage. Undersizing thicknesses just to reduce costs and space can impair this feature, while oversizing brings no benefits but only extra costs. It is important to comply with safety standards and manufacturers’ guidelines.

Disregarding Creepage Distances and Clearances

Creepage distances between conductors and external clearances on insulating materials are key parameters to prevent disruptive discharges, arcing and short circuits. When installing switchboards, cables and other components, it is essential to respect the minimum distances and dimensions required by national (CEI) and European (EN) standards.

Using Deteriorated electrical Insulating Materials

Over time and use, insulators can deteriorate due to thermal, mechanical, chemical stresses and other environmental factors. It is good practice to periodically inspect their conditions and replace damaged or excessively aged ones if necessary. Do not skimp on maintenance and never use damaged or compromised insulators.

Disorderly Laying of Cables and Conductors

A cluttered and close laying of cables and conductors can result in reduced creepage distances below safety levels. It is better to organize the installation using ducts, ties, false ceilings and other orderly systems.

Inadequate Fastening of electrical Insulators

Insulators must be installed stably, resistant to vibrations, tears and other stresses. Poor fastening can cause their shifting and damage. Choose suitable installation methods and support materials.

In addition to these precautions, for a system that meets standards it is advisable to consult the technical documentation of the chosen insulators and the guidelines of the Italian Electrotechnical Committee (CEI). For specific advice, contact a qualified electrician.

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