What should the insulation resistance value be for most cables to ensure safety?

For most cables, the minimum insulation resistance value of 1 megohm is considered a safety standard. Insulation resistance is essential in determining how well the insulation of a cable can prevent current leakage to the ground or to other conductors. A value of 1 megohm serves as a benchmark that indicates the insulation is generally in acceptable condition, helping to prevent electrical shocks and short circuits, thereby ensuring safe operation of electrical systems.

Values below this threshold may indicate deterioration or damage to the insulation, which poses risks. While higher values, such as 5 or 10 megohms, indicate even better insulation quality, they are not the minimum standard required for safety across most applications. This makes the 1 megohm minimum a practical requirement for many situations involving standard cables. The lower options, like 0.1 megohm, do not meet the safety criteria for reliable insulation in most electrical installations.