Earthing Resistance Test
1. Purpose:
The requirements are specified in order to ensure that exposed metal is effectively
connected to the main earth terminal of the appliance.
2. Application:
Class 0I and class I appliance.
3. Test Apparatus:
Having a no-load voltage not exceeding 12 V (a.c. or d.c.) and equal to 1.5 times rated
current of the appliance or 25 A, whichever is the greater.
4. Special Instruction:
a. The resistance of flexible cable or cord is not included in the measurement.
b. Care is taken that the contact resistance between the tip of measuring probe and
the metal part under test does not influence test result.
c. Current is passed between the earthing terminal or earthing contact and each of
the accessible metal parts in turn.
5. Test Procedure:
a. Connect the test probe to the earthing terminal or earthing contact and the
accessible metal parts.
b. Adjust the test equipment until the current reach 1.5 times rated current of the
appliance or 25 A, whichever is the greater. The test period set at 60s.
c. Press the test button and read the maximum resistance.
6. Evaluation of test result:
The earthing resistance shall not exceed 0.1 Ω
Eason Wang
Eason Wang