General requirements, test methods and practical guidance
IEC 60352-7-2020 pdf download.Solderless connections — Part 7: Spring clamp connections — General requirements, test methods and practical guidance.
— a specified conductor, properly inserted into a terminal, is allowed to be deflected in any of the 12 directions differing from each other by 30°. with a tolerance referred to each direction of ±5° and;
— the starting point can be varied by 10° and 20° from the original point. A reference direction need not be specified.
The deflection of the conductor from its straight position to the testing positions shall be effected by means of a suitable device applying a specified force to the conductor at a certain distance from the terminal.
The deflecting device shall be so designed that:
— the force Is applied in the direction perpendicular to the undeflected conductor;
— the deflection Is attained without rotation or displacement of the conductor within the clamping unit, and
— the force remains applied whilst the prescribed voltage drop measurement is made.
Provisions shall be made so that the voltage drop across the spring clamp termination under test can be measured when the conductor is connected, as shown for example in Figure 3.
b) Test method
The specimen is mounted on the fixed part of the test apparatus in such a way that the specified conductor inserted into the spring clamp termination under test can be freely deflected.
The surface of the test conductor shall be free of detrimental contamination or corrosion.
NOTE If necessary, the inserted conductor can be permanently bent around obstacles, so that these do not influence the results of the test.
In some cases, with the exception of the case of guidance for the conductors, it may be advisable to remove those parts of the specimen which do not allow the deflection of the conductor corresponding to the force to be applied.
A spring clamp termination is fitted as for normal use with a solid copper conductor having the smallest cross-sectional area as specified by the manufacturer and is submitted to a first test sequence; unless the first test sequence has failed, the same spring clamp termination is submitted to a second test sequence using the conductor having the largest cross-sectional area.
The force for deflecting the conductor is specified in Table 2, the distance of 100 mm being measured from the extremity of the terminal, including the guidance for the conductor, if any, to the point of application of the force to the conductor.
The test is made with continuous current (i.e. the current is not switched on and off during the test); a suitable power supply should be used so that the current variations are kept within ±5 % during the test.
C) Test procedure
A tenth of the test current assigned to the wire according to Table 4 is passed through the
spring clamp connection under test. A force, according to Table 2, is applied to the test
conductor inserted in the spring clamp termination under test in the direction of one of the
12 directions shown in Figure 3 and the voltage drop across this spring clamp connection
is measured. The force is then removed.
The force is then applied successively in each of the remaining 11 directions shown in Figure 3 following the same test procedure.
If at any of the 12 test directions the voltage drop is greater than 2,5 mV, the force Is kept applied in this direction until the voltage drop is reduced to a value below 2,5 mV, but for not more than 1 mm. After the voltage drop has reached a value lower than or equal to 2,5 mV, the force is kept applied in the same direction for a further period of 30 s during which period the voltage drop shall not have increased.
The other specimens of the set are tested following the same test procedure, but moving the 12 directions of the force so that they differ by approximately 100 for each specimen. If one specimen of the set has failed at one of the directions of application of the test force, the tests are repeated on another set of specimens, all of which shall comply with the repeated tests.IEC 60352-7-2020 pdf download.