AS 62052.21:2018 pdf download.Electricity metering equipment (ac)-General requirements, tests and test conditions Part 21: Tariff and load control equipment (IEC 62052-21:2016 (ED.1.1) MOD).
5 Mechanical requirements and tests
5.1 General mechanical requirements Tariff and load control equipment shall be designed and constructed in such a way as to avoid introducing any danger in normal use and under normal conditions, so as to ensure especially • protection against electrical shock, see IEC 62052-31:2015, Clause 6; • protection against mechanical hazards and stresses, see IEC 62052-31:2015, Clauses 7 and 8; • protection against spread of fire, see IEC 62052-31:2015, Clause 9;
• personal safety against effects of excessive temperature, see IEC 62052-31:2015, Clause 10; • protection against penetration of dust and water, see IEC 62052-31:2015, Clause 11; • protection against liberated gases and substances, explosion and implosion, see IEC 62052-31:2015, Clause 12. All parts, which are subject to corrosion under normal working conditions shall be effectively protected. Any protective coating shall not be liable to damage by ordinary handling, or damage due to exposure to air, under normal working conditions. Tariff and load control equipment shall have adequate mechanical strength and shall withstand the elevated temperature which is likely to occur in normal working conditions. The components shall be reliably fastened and secured against loosening. The construction of tariff and load control equipment shall be such as to minimize the risks of short-circuiting of the insulation between live parts and accessible conducting parts due to accidental loosening or unscrewing of the wiring, screws, etc.NOTE For tariff and load control equipment for special use in corrosive atmospheres, additional requirements shall be fixed in the purchase contract (for example, salt mist test according to IEC 60068-2-11). See also IEC 62052-31:2015, 6.5.2.2, 6.9.1 and 6.9.7.3.
5.2 Case 5.2.1 Requirements Tariff and load control equipment shall have a case which can be sealed in such a way that the internal parts of the equipment are accessible only after breaking the seal. The case shall be designed according to protective class I or II.The cover shall not be removable without the use of a tool. The case shall be so constructed and arranged that any non-permanent deformation cannot prevent the satisfactory operation of the tariff and load control equipment.
5.2.2 Mechanical tests  The case shall be subjected to the following tests. NOTE The back-up power supply, if any, shall remain connected.
5.2.2.1 Spring hammer test The test shall be performed as part of safety testing, as specified in IEC 62052-31:2015, 8.2.
5.2.2.2 Shock test The test shall be carried out according to IEC 60068-2-27, under the following conditions: — tariff and load control equipment in non-operating condition, without the packing; — half-sine pulse; — peak acceleration: 30 g (300 mIs2); — duration of the pulse: 18 ms. After the test, the tariff and load control equipment shall show no damage or change of information and shall operate correctly in accordance with the requirements of the relevant standard.
5.2.2.3 Vibration test
The test shall be carried out according to IEC 60068-2-6, under the following conditions:— tariff and load control equipment in non-operating condition, without the packing; — frequency range: 10 Hz to 150 Hz; — transition frequency: 60 Hz; — f< 60 Hz constant amplitude of movement ±0,075 mm;
— f> 60 Hz constant acceleration 9,8 mIs2 (1 g); — single point control; — number of sweep cycles per axis: 10. NOTE Ten sweep cycles = 75 mm.
After the test, the tariff and load control equipment shall show no damage or change of information and shall operate correctly in accordance with the requirements of the relevant standard.
5.3 Window
If the cover is not transparent, one or more windows shall be provided for reading the display and observation of the operation indicators if fitted. These windows shall be of transparent material, which cannot be removed without breaking the seals.
5.4 Terminals, terminal block(s), protective earth terminal See IEC 62052-31:2015, 6.5.2, 6.9.5 and 6.9.7.
5.5 Terminal cover(s) See IEC 62052-31:2015, 6.9.4.
5.6 Clearance and creepage distances See IEC 62052-31:2015, 6.7.
5.7 Insulating encased tariff and load control equipment of protective class II See IEC 62052-31:2015: • 3.6.8, (Protective) class II equipment:
• 5.4.5.1, Protective class and earthing; • 6.5.2, Protective bonding; • 6.8 Insulation requirements between circuits and parts, and Annex B, Examples for insulation between parts; • 6.9.2, Insulating materials.AS 62052.21 pdf download.