In the 200kA SCCR (Short Circuit Current Rating) test of an SPD under UL 1449 5th Edition, 200kA current is not directly applied to the MOV (Metal Oxide Varistor) or GDT (Gas Discharge Tube) elements inside .

 

1. 200kA SCCR is the maximum "short circuit current" that the entire SPD can withstand during a surge fault . This test evaluates the SPD's ability to withstand high current environments that may temporarily inflow during actual electrical equipment failures, without a circuit breaker or fuse within the SPD. This is different from the test in which a surge exceeding the rating (e.g., 8/20μs waveform) is repeatedly directly applied to the MOV or GDT.

2. While protective devices such as MOVs and GDTs may be subjected to current as part of the SCCR test, it is extremely rare for the full 200kA current to be applied to the device. In most cases, the circuit breaker (thermal fuse, disconnector, circuit breaker, etc.) within the SPD will take precedence, protecting the device from fire or explosion.

3. Many SPDs insert multiple MOVs in parallel, so that in reality only the current distributed across one element is applied.

4. In the case of GDT, if 200kA flows directly, there is a very high possibility that the element will be destroyed, and to prevent this possibility, the SPD circuit design necessarily includes a blocking element and a protection device , and the entire configuration is evaluated to see if it can withstand a 200kA short-circuit environment.

 

In other words, the SCCR 200kA test is a test to determine whether the SPD itself can safely withstand the maximum short-circuit fault current when installed in a circuit. The 200kA current is not directly applied to the MOV or GDT element itself. In reality, the SPD's built-in circuit protection system, such as the circuit breaker, absorbs a portion of the total current or blocks it to protect the element.

 

The fabrication and certification procedures for SPD (Surge Protection Device) samples through 200kA SCCR (Short Circuit Current Rating) test under UL 1449 5th Edition are as follows.

 

SPD sample fabrication and preparation

• Sample Preparation: Typically, a finished product or SPD in an actual installation form (e.g. DIN-rail type, plug-in modular type, etc.) is prepared to be identical to the actual usage environment.

• Quantity Required: Additional samples may be required for each test current level (e.g., 200 kA SCCR), and UL standards require a minimum of eight samples for SCCR testing. Some non-SPD components may be exempt from certain tests (e.g., withstand voltage, insulation resistance) if they contain special circuitry (e.g., status indicator circuitry).

• Specification Attachment: The sample must be able to identify the main specifications of the product, such as rated voltage, MCOV, VPR, protection method, etc., and the structure, component spacing, heat dissipation conditions, etc. must also be manufactured to meet the specifications.

 

200kA SCCR test procedure

• Test Method: The SPD is tested under conditions where a short-circuit current of 200 kA is applied without an external circuit breaker (CB) or fuse. This test verifies the SPD's inherent fault-relief capabilities (e.g., arc protection, self-protection, etc.).

• Test Equipment: Testing is performed in an accredited laboratory (e.g., a UL-certified testing laboratory) and is performed under test current conditions (defined waveform, duration, etc.) that are consistent with the SCCR.

• Pass Criteria: After testing, the SPD sample must meet all of the following conditions:

1. There should be no arcing, sparking or structural damage.

2. There will be no risk of fire or electric shock at the approved current.

3. Residual or leakage current within the circuit shall not exceed safety standards.

4. Additional inspection after cooling (after a certain period of time or reaching ambient temperature) immediately after testing

• Final Verification: All samples undergo a final verification after testing to ensure they maintain normal insulation and structural integrity. If the test passes, the tested SCCR (200 kA) is officially certified for the SPD model.

 

Verification completed

• Official Certification: SPDs that pass the test must be officially certified with the UL 1449 5th Edition certification mark and an SCCR rating (e.g. 200kA), and can then be shipped to the market as a “UL Listed/Recognized” product.

• Audit Procedure: During the certification process, test reports, all procedure history, and certification status of material components must be documented, and retesting may be requested if necessary.

 

In summary, the 200kA SCCR test of SPDs in UL 1449 5th standard is strictly performed on samples that simulate actual use conditions, and certification is granted only to products that pass various structural and electrical acceptance criteria.