Laboratory

Laboratory of Metalka Majur is engaged in the development and verification of the products within the field of electrical installation material from its own production program. Quality control and assurance of the products are enabled through three types of activities:

• Support to developing activities through comprehension of the design solutions and their compliance with the requirements of the current (applicable) standards, due to the development of the new products and upgrading of the existing ones.
• Quality verification of the finished product in compliance with the requirements of the appropriate quality standards due to obtaining the adequate attests on the target market.
• Quality monitoring of the products being in regular serial production through application of the suitable internal and general standards on randomly selected samples, taken from the production in accordance with the defined plan of the periodical testing.

Laboratory is specially equipped for testing in compliance with IEC standards, as follows:

• Switches for stationary electrical installations up to 16A/250V;
• Connection accessories (receptacles and plugs) and installation boxes for household and similar purposes of 16A/250V.

Testing conducted by the Laboratory in compliance with IEC 60669-1 and IEC 60884-1 standards are:

1. Switching Power; Switches are subject to 200 switchovers under the voltage 1.1 higher than the designated voltage and current 1.25 times higher than designated current and power factor of cos φ= 0.3.
2. Normal Operation; This test is used for inspecting the endurance of switches and receptacles to mechanical, electrical and thermal strains during normal use. Switches are subject to 40,000 switchovers under the designated voltage, designated current and cos φ= 0.8. Test plug is inserted and removed 5,000 times into the receptacle under the same conditions.
3. Power of Interruption; The test plug is inserted and removed 50 times into receptacles under the trial voltage 1.1 times higher than designated voltage, current 1.25 times higher than designated current and cos φ = 0.6.
4. Electric Shock Protection; Inspection of inaccessibility of live parts when the switch or receptacle is installed like under normal use. The testing is made using appropriate standard test finger and limit gauges.
5. Testing of Connections; Testing of connections includes:
   • - reliability test on tightening of the conductors;
   • - test on mechanical strength of the connections;
   • - test on tightening of the conductors without damage;
   • - reliability test of conductors’ grip, etc.
6. Aging- and Moisture-Related Reliability; Resistance test on aging of the switches and receptacles is carried out in the chamber under the temperature of 70°C±2°C within the continuous period of 168 hours. The elevated humidity of 91% to 95% is exposed to:
   • - ordinary switches (IP20) within continuous period of 48 hours and
   • - switches with IP44 protection within continuous period of 168 hours
7. Insulation Resistance and Dielectric Strength; Tests are conducted upon exposure to the conditions of elevated moisture. The insulation resistance is measured using one-way voltage of 500V. Dielectric strength is tested in such a way that the insulation is exposed to voltage of 2000V within one minute. The break-over (sparkle) or disruptive discharge shall not occur during testing.
8. Temperature Increase; Testing implies the measurement of temperature increase for the connections of switches and receptacles under test current 25-35% higher than rated current of the switch type.
9. Mechanical Strength; Mechanical strength testing of the switches and receptacles is used for inspecting their capability to endure strains, appearing during the installation and use.
10. Heat Resistance:
    • Heat resistance test of switches, receptacles, installation boxes, etc. is conducted within the chamber under temperature of 100±2°C within 1hour.
    • Parts of the insulation material required for gripping the parts with current flow are subject to ball test within the chamber at the temperature of 125±2°C.
    • Parts of the insulation material required for gripping the parts with current flow are subject to ball test within the chamber at the temperature of 70±2°C.
11. Mechanical Strain Testing of Joints; Electrical and mechanical joints are subject to test of their endurance to mechanical strains, created during normal use.
12. Resistance to creating conducting paths - CTI; Insulation parts, securing live parts, are tested.
13. Corrosion Resistance; Corrosion resistance is tested on the iron parts (metal frame, screws, lugs...).
14. Test on Durability of Designations; The designations, which shall be durable and easy to bend (rated current, rated voltage, type,...) are tested to endurance. Testing is made by treating the designation using water first, then denatured alcohol.