What is the maximum permitted earth conductor resistance when testing an appliance supply plug?

The maximum permitted earth conductor resistance when testing an appliance supply plug is 1Ω. This value is critical for ensuring safety and effective operation of the electrical equipment. A low earth resistance means that in the event of a fault, the electrical current can flow back to the ground effectively, reducing the risk of electric shock or fire.

When the earth conductor resistance is at or below 1Ω, it ensures that there is minimal voltage drop and that any fault current is capable of tripping protective devices, like circuit breakers or RCDs. This level of resistance allows for sufficient current to flow during a fault condition, keeping users safe from potential electrical hazards.

Values above 1Ω might lead to unreliable fault current paths, increasing the risk of electric shock or equipment damage. Therefore, maintaining a maximum earth conductor resistance of 1Ω is a key safety standard in electrical installations.