EN
LVD Earth Continuity Test
LVD earth continuity test: low resistance between protective conductor and body, terminal audit assessed against standard limits, reported.
The LVD earth continuity test verifies the connection resistance between the protective conductor (PE) and touchable non-conductive metal surfaces (body, door, cable gland armour, movable parts) using a high-current (typically 10-25 A DC) measurement. This test is the physical foundation of LVD safety, ensuring that fault current flows through the protection path and really trips the protective device: with broken continuity, leakage current returns through the person to earth and touch voltage stays dangerous.
Method and Rules
- Measurement current: Above 10 A DC is applied for low-resistance measurement; probe contact resistance is zeroed (Kelvin/4-point) for sensitive reading. Unlike low-current continuity checks, paint-surface oxide is penetrated to confirm true metallic contact.
- Measurement points: Plug-socket earth pin to every touchable metal; also the PE-bar terminal connection and door-hinge flexible links. Painted surfaces are scraped at the contact point — no paint-insulation is accepted.
- Acceptance: Practically the upper bound is 0.1 Ω (or manufacturer/standard value); TS EN 60204-1 demands the protective circuit impedance to stay within the defined fraction of fault impedance. The firm limit is computed from earthing system (TN/TT), network fault current and RCD tripping value: Z×Ia ≤ U0 governs.
- Complementary items: Cable section-kink-damage control, loose nut-torque marks, splice-terminal burn traces and broken braid scan. Flexible connection fatigue is the priority finding on constantly moving parts (door, carrier table).
Interpretation
High resistance arises from loose terminals, oxidised connections, broken earth braid or wrong bolt-washer combinations. Slightly above limit is removed by cleaning-tightening and remeasured; well above, the line is renewed. If continuity is good yet voltage appears on the body, the fault is on the network side (neutral-earth bridge, shared earthing). On portable equipment with triple adapters, continuity should be checked faster together with the leakage test; a monthly field visual programme is recommended.
Legislation and Outcome
The test is a mandatory item in the periodic inspection programme under 2014/35/EU LVD, Law No. 6331, the Earthing Regulation and Internal Electrical Installations Regulation. References are TS EN 60204-1, IEC 62353 and IEC 61557-4. The result connects to a signed report with the measurement point table, resistance values, acceptance comparison and remediation proposals. Continuity tests are in our PL Analysis and LVD Tests set; for the connection side see Earthing Inspection and Terminal Inspection, or contact us for an appointment.
FAQ on LVD Protective Earth Continuity Test
If the protective conductor (PE) is broken-loose-high-resistance, the current leaking to the body on an insulation fault cannot return to earth; touch voltage appears and the relay trip delays or fails. Continuity is the foundation of the leakage-protection chain; therefore it is measured before the insulation-HV test with a low-resistance ohmmeter (low voltage high current; 200-300 mA steady). Measurement points: socket-chassis-body-screen-bar to main earth terminal; cable-joint-splice along the whole line.
On class I devices the continuity resistance sits in the typical sub-0,1 ohm band (cable length-cross-section reference; IEC 62353 / VDE 0701-0702 logic); on fixed installation main-connection-earth systems the reading carries a different threshold. Above-limit-suspect: loose-oxidised terminal, broken splice box, skipped screen clamp, short screw, surface-fit busbar. The measurement manages cable-resistance subtraction (Kelvin), contact-surface cleanliness-probe pressure-duration.
Plug earth pin to body; terminal-chassis-panel bar; motor-machine body-cable entry; screen-armour clamping; portable reel-cable splice; rectifier-transformer cooler metal parts; rail-cabin-guard-screen metal parts. Class II (no-earth double insulation) and class III (SELV) devices hold a different PE expectation; wrong classification makes the reading meaningless. In panel series test (TS EN 61439-1) continuity also covers body-cabinet bar and door-hinge bonding.
First item in the hand-tool periodic rotation (VDE 0701/0702 logic); tool-panel-investment-change-fault aftermath; facility periodic control (installation inspection) coordinated with earth-system measurement. On failure: connection verification-retorque-change-corrosion removal-retest. Report source: value-measure point-specification limit-device calibration; followed on site with a date label. A line with suspected broken PE leaves supply — this is the first rule.