I. What is a routine test?
A routine test is a test to which each device is subjected after or during manufacture. The test helps identify failures and/or unacceptable tolerances in manufacturing that functionality tests may not detect and may create an electrical hazardous situation. The purpose of routine tests is to evaluate several safety parameters which the manufacturing process could affect. E.g. wiring-related issues, warning labels, core transformers, and insulation.
Routine tests are an essential element of the follow-up inspections conducted at factory locations of certified electrical products. They make it possible to guarantee that an electrical product is functional and safe and all necessary procedures are being maintained at an acceptable level.
II. How to perform routine tests?
To perform a routine test, manufacturers must:
- Follow relevant product safety standards
- Have the electrical product fully assembled
- Ensure that the equipment is not unwired, disassembles or modified in any way
- Ensure that the product is not energised during the tests; however, the mains switch should be in the ON position.
During the test, manufacturers should evaluate the product’s dielectric strength, grounding continuity and leakage currents in normal conditions.
Dielectric strength test is a voltage test for the following:
- Basic insulation applied between the mains terminals and grounded reachable conductive parts.
- Double insulation applied between the low-voltage reachable conductive parts (incl. terminals) and the mains terminals.
During the test, the voltage is raised to its specified value within 10 seconds and maintained for a maximum of 2 seconds. In the meantime, no breakdown or repeated flashover should occur.
A dielectric strength test should:
- never be performed on energised circuitry or equipment
- be conducted only by qualified employees
- be performed on a nonconducting table or workbench
- never be performed in an explosive atmosphere or environment.
Additionally, there shouldn’t be any floating metal in the space between the test operator and the location where the product is being tested. The test area should be kept clean and uncluttered.
A grounding continuity test is performed with a grounding continuity tester. The test is made between, on one side, the earth pin of the appliance inlet or the mains plug for non-detachable power supply cords and, on the other, all grounded accessible conductive parts that can be energised in an SFC. The test current should not have a specified value during the test, and the ground wire should be flexed along its length. If any changes in the continuity indication occur, it means that the ground connection is damaged.
The leakage current test is conducted with an MD that consists of capacitive and resistive networks designed to simulate the human body’s impedance. For this test, the electrical equipment should be energised, and the following factors should be evaluated:
- earth leakage
- touch current
- patient leakage current (only for medical equipment)
If a routine test is performed incorrectly, the entire equipment can be damaged.
III. Test records for routine tests
Product safety standards define the documentation that manufacturers should maintain with respect to routine tests. Usually, test records of the calibration should be made available to factory inspectors.
A test record should contain the following elements:
- Equipment information (e.g. description, manufacturer and model, and calibration due date)
- Dielectric strength test report, including description, expected results, results breakdown, and pass/fail indication.
- Earth continuity test report containing the following data: description of test points, expected results, and pass/fail indication.
- Leakage current test report, providing the following information: description, expected results, measured current, and pass/fail indication.
- Name and signature of the employee who performed the tests
- Name and signature of the person who verified the test results
BONUS: Free download – A template of a test record sheet for recording test results produced by routine tests.
IV. Harmonised standards for routine tests
For setting up the routing tests, manufacturers should use a relevant harmonised or non-harmonised standard. In this regard, the following standards exist:
- EN 50106 – Safety of household & similar electrical appliances
- EN 62911:2016 – Audio, video & IT equipment. Routine electrical safety testing in production.
- EN 50580 – Safety of hand-held electric motor operated tools.
- EN 61010-1 – Safety requirements for EEE for measurement, control & laboratory use.
- IEC/UL 61010-1 – Safety requirements for EEE for measurement, control & laboratory use.
- EN 60598 – Luminaries
- IEC 62911 – Audio, video & IT equipment. Routine electrical safety testing in production.
- ENEC 303 – Routine test requirements for manufacturers.