IGCSE Physics 2025 – 400 Free Practice Questions to Pass the Exam

When an appliance is described as double insulated, it signifies that the appliance has two layers of insulation to protect users from electrical shock. This means that there is an additional layer of non-conductive material which safeguards the internal electrical components, providing extra security beyond the basic insulation that prevents parts of the appliance from being live.

Typically, this design allows the appliance to operate safely without the need for a grounding wire, as the two insulation layers provide sufficient protection against electric shock. Therefore, it is particularly important in appliances that are used in environments where moisture or water may be present, although it does not imply that the appliance is safe for use underwater.

A double insulated appliance is also visually identifiable because it often features a specific symbol, usually a square within a square. This symbol indicates that the appliance does not require grounding, reinforcing that the insulation alone is adequate to ensure user safety.