Mass continuity

Principle of the earth continuity test

• This test is also known as the earth continuity test or protective conductor test.
• It is only applicable to Class 1 products (products that have a protective conductor).
• The objective is to ensure that all metal parts of the product are properly connected to the main earth.
• This test must be performed first in order to guarantee operator safety and because the other tests require the product’s earth to have been validated (high voltage, insulation, standard leakage).
• The resistance of the earth circuit can be measured using a 2-wire or 4-wire method (in the 4-wire method, the voltage drop in the cables is not taken into account in the measurement)
• Use of high current and low voltage, generally 10–30 A / 6–12 VAC (safety voltage)
• All accessible metal parts must be tested with a test probe or clamp
• The resistance must generally be less than 100 mΩ (500 mΩ for luminaires)
• Only one standard (EN60204) does not require resistance to be measured, but rather the voltage drop