IEC60598-1 Clause 4.26 Figure 29 Uninsulated reverse polarity SELV component accidental short circuit protection test chain

1、Introduce

According to the requirement of IEC60598-1 clause 4.26 Figure 29. Used for accidental short circuit protection testing of SELV components that are not insulated and have opposite polarity that can be touched in lighting fixtures. The test chain is made of Cu63% and Zn37% uncoated metal.

2、Method of application:

The chain shall have a resistance value of  2.5 ± 20% Ω/m, and verify the resistance of the test chain before each measurement.

Measure the spatial distance between the two poles of the SELV component, denoted as X, in centimeters/cm.

Hang standard counterweights of 15 * X * g or 250g at both ends of the test chain.

Install thermocouples at appropriate locations on the tested sample and turn on the temperature monitoring device.

Connect the sample to a power supply of 0.9~1.1 times the rated voltage.

Place the test chain and conduct a short-circuit test.

Attention: Melting of the test chain may cause burns.

3、Attention:

The test chain is made of copper zinc alloy product, which has no coating on the surface and is prone to oxidation. Please pay attention to maintenance.

When the resistance fluctuates, ultrasonic cleaning or soaking in weak acid at a concentration of 0.5% can be used.

Excessive weight distribution can cause a decrease in wire diameter.