- Class I appliances are potentially the most dangerous appliances.
- An earth bond test is only applicable to a class 1 appliance with exposed conductive parts.
- A PAT tester does an Earth Bond or Earth Integrity Test, which shows whether the earth conductor is in a satisfactory condition. A multimeter or insulation tester will only locate a fault when there is a complete break present in the conductor.
- The earth bond test measures the resistance of the earth from the pin of the mains supply plug to the earthed body of the appliance and indicates how good the connection is.
- The earth bond test probe is connected to the appliance earthed reference point and acts as a return.
- General rule of thumb given by the IEE is that the test current chosen is 1.5 times the rated current of the appliance, with a maximum of 25A. The pass value is normally (0.1 + R) Ohms where R is the resistance.
- If a reading is less than 0.1 Ohms then the results is a PASS.