Created by: Glen Zhu | Updated Date: November 1st, 2024
Applicable countries: United States
The UL standard is developed by Underwriters Laboratories Inc. in the United States.
IEC 61643-11-2011 Low-voltage surge protective devices – Part 11 Surge protective devices connected to low-voltage power systems – Requirements and test methods
IEC 61643-31-2018 Low-voltage surge protective devices – Part 31 Requirements and test methods for SPDs for photovoltaic installations
Applicable countries: International
IEC standards are developed by the International Electrotechnical Commission (IEC), which is a global organization for standardization in the fields of electrical, electronic, and related technologies. Its member organizations include national standardization bodies, industry associations, manufacturers, user groups from more than 150 countries and regions.
These requirements cover enclosed and open-type Surge Protective Devices (SPDs) designed for repeated limiting of transient voltage surges as specified in the standard on 50 or 60 Hz power circuits not exceeding 1000 V and for PV applications up to 1500 V dc.
Surge Protective Device (SPD) Definition:
A device composed of at least one non-linear component and intended for limiting surge voltages on equipment by diverting or limiting surge current and is capable of repeating these functions as specified.
This part of IEC 61643 is applicable to devices for surge protection against indirect and direct effects of lightning or other transient over-voltages.
These devices are packaged to be connected to 50/60 Hz a.c. power circuits, and equipment rated up to 1 000 V r.m.s. Performance characteristics, standard methods for testing and ratings are established.
Surge Protective Device (SPD) Definition:
These devices contain at least one nonlinear component and are intended to limit surge voltages and divert surge currents.
Note 1: An SPD is a complete assembly, having appropriate connecting means.
Note 2: It can include a second function, such as current limiting function (to be considered in future new standards).
Note 3: Nonlinearity caused by frequency changes.
Note 4: IEC61643-3XX series standards cover surge protection components.
| UL1449 | IEC 61643 |
| Finished product category (Listed): Classified according to the installation position of SPD. | Classify according to the experimental waveform. |
| Complete assembly:
|
Classify according to the experimental waveform:
| |
| Recognized Component: Type 5 Type 4 Component Assemblies Type 1, 2, 3 Component Assemblies | Component: MOV testing according to IEC 61643-331 GDT testing according to IEC 61643-311 |
Type 1 SPD: Main load side (position from transformer secondary side to front of circuit breaker).
Type 2 SPD: Branch load side (installed at the load end of the distribution device overcurrent circuit breaker, including distribution branch).
Type 3 SPD: End side (installed at least 10 meters away from the distribution panel).
Note: UL distinguishes one-port and two-port based on whether or not the device provides current to power loads.
Thermal Fuse Metal Oxide Varsitor
Type 1, 2, 3 Component Assemblies (Type 1, 2, 3 CA)
Differentiation of SPD protection functions for electronic components
| Differentiation of SPD protection functions for electronic components | ||||
| SPD Type | Surge protection function | Thermal protection | Short-circuit protection | Application |
| Type 5 | √ | N/A | N/A | N/A |
| Type 4 CA | √ | √ | N/A | N/A |
| Type 3 CA | √ | √ | √ | Impermanent fixation |
| Type 2 CA | √ | √ | √ | Permanent fixation |
| Type 1 CA | √ | √ | √ | Permanent fixation |
| Note: | 1. Surge protection function: SPD provides surge protection for components installed at the back end of the circuit. 2. Thermal protection: Thermal protection when SPD fails. 3. Short-circuit protection: Short-circuit protection when SPD fails. | |||
Type SPD | VPR | In or Nominal load cycle |
Type 1, 1CA | 6kV/3kA | 10 or 20 kA |
Type 2, 2CA | 6kV/3kA | 3, 5, 10 or 20 kA |
Type 3, 3CA | 6kV/3kA | 6kV/3kA |
Type 4 CA | N/A | 0.01, 0.05, 0.1, 0.15, 0.25, 0.5, 1.5, 2, 2.5, 3, 5, 10 or 20 kA |
Type 5 | N/A | 0.01, 0.05, 0.1, 0.15, 0.25, 0.5, 1.5, 2, 2.5, 3, 5, 10 or 20 kA |
Type SPD | Current Test Level | ||
Short-circuit Current | Intermediate Current | Limiting Current | |
Type 1, 1CA, 2, 2CA | Min. 5 kA, Max. 200 kA | 1000 A, 500 & 100 A | 10, 5, 25 & 0.5 A |
Type 3, 3CA | N/A | 5000*, 3500*, 2000*, 1000*, 150 & 50 A | 5, 2.5, 0.5, 0.125, & 0.06 A |
Type 4 CA | N/A | N/A | 10, 5, 2.5, 0.5, 0.125, & 0.06 A |
Type 5 | N/A | N/A | N/A |
Note:* Determine the test current based on the voltage and total power of the SPD system. | |||
Thermal Protection / Thermal Disconnect – parallel connection
Thermal Protection / Thermal Disconnect – series connection
Testing for Type 5 and Type 4 Component Assemblies
| Test | Section reference | Type 5a | Type 4 component assembliesa |
| Temperature | 40 | Oa | Oa |
| Vn (before and after ln) | 70 | A | A |
| Nominal Discharge Current (ln) | 42, 43 | A | A |
| Disconnector | 46, 47, 48 | N/A | A |
| Limited Current | 45 | N/A | A |
| Dielectric Voltage Withstand (for discrete components the test is performed with foil wrapped around epoxy disc) | 39 | A | A |
| Grounding Continuity | 49 | O | O |
| Fault and Overcurrent Tests only as required by Exception No. 2 of 11.18 and 11.19 or by 22.3 or 22.4 | 50, 51 | O | O |
| Withstand | 52 | Ob | Ob |
| Insulation Resistance and Capacitor Endurance | 54, 55 | O | O |
| Component Breakdown as required by 23.1 | 56 | O | O |
| A – Applicable NA – Non-applicable O – Only as applicable a – Applicable to one-port SPDs with heat-generating components, such as inductors, resistors, etc., and all two-port SPDs. b – Applicable to two-port SPDs. | |||
Thermal Disconnect Testing
UL Standard | Test | Specimens | |||||||
| A | B | C | D | E | H | I | J | ||
| 60691 | Temperature and Humidity Cycle Conditioning a | × | × | × | |||||
| 60691 | Dielectric Strength (if applicable) b | × | × | × | |||||
| 60691 | Insulation Resistance (if applicable) b | × | × | × | |||||
| 1449 | Surge Testing Sequence | × | × | × | |||||
| 60691 | Temperature Tests – Aging – Step 1, 21 days c | × | × | × | × | ||||
| 1449 | Limited Current Abnormal Overvoltage Test d, e | × | × | × | × | × | × | × | × |
| 60691 | Dielectric Strength (if applicable) b | × | × | × | × | × | × | × | × |
| 60691 | Insulation Resistance (if applicable) b | × | × | × | × | × | × | × | × |
| a The Temperature & Humidity Cycle Conditioning is conducted as detailed in UL 60691 except that 24 hour Temperature Conditioning is conducted at 60°C, the maximum rated Ambient Air Temperature or the maximum temperature measured on the disconnect means, during the Temperature Test of Section 40 of UL 1449, whichever is greater. Temperature Conditioning of component assemblies with a varistor shall be conducted at minimum 85°C unless the Metal Oxide Varistors are limited to an end-use temperature between 60°C and 84°C. Testing may be conducted in a test chamber with a ±2°C temperature tolerance. b If Acceptable Results are obtained between Disconnection Means (between open contacts) for both the Dielectric Strength and Insulation Resistance Tests, a discrete component “board level” Type 4 Component Assemblies does not need to comply with the Dielectric Strength and Insulation Resistance Testing requirements, between Live Part and the body of the discrete component (wrapped in foil) provided the conditions of use indicate that there was dielectric breakdown between live parts and the body of the discrete component (wrapped in foil).As such, proper spacings will need to be maintained between the discrete component, other live parts and dead-metal parts. c Step 1 of the Aging portion of the Temperature Tests is conducted as detailed in UL 60691 except that 100% of the specimens shall not have functioned and Aging is conducted at 60°C, the maximum rated Ambient Air Temperature or the maximum temperature measured on the disconnect means, during the Temperature Test of Section 40 of UL 1449, whichever is greater. Aging of component assemblies with a varistor shall be conducted at minimum 85°C unless the Metal Oxide Varistors are limited to an end-use temperature between 60°C and 84°C. Testing may be conducted in a test chamber with a ±2°C temperature tolerance. d To be conducted for each Limited available short circuit current test level, as detailed in Table 45.4 of UL 1449, that the disconnect means is being relied to comply 45.4. e The samples shall not be disturbed until they have been allowed to cool for 15 minutes maximum or cool down to within 10°C of ambient. | |||||||||
| Note 1 – Eight additional samples are required for the test program for each Limited available short circuit current test level, as detailed in Table 45.4 of UL 1449, that the disconnect means is being relied to comply with 45.4. Note 2 – If the identification of the thermal element material has not been previously determined by UL, then the material will need to be subjected to the Differential Scanning Calorimeter test for identification. Note 3 – Special Samples for testing may be required. Specifically, if the SPD employs status circuitry or other non-SPD discrete components, that would conduct during the Dielectric Strength and Insulation Resistance Tests, those components may be omitted for these tests. Note 4 – Unless Sequence H is being conducted as representative of the as-received Nominal Discharge Current Testing. Nominal Discharge Current Testing of sequences A, B and H can be conducted without applying MCOV. | |||||||||
UL standard and IEC standard: comparison of test waveform parameters
Standard | IEC61643-11, IEC61643-31 | UL1449 |
Maximum discharge current Imax (8/20µs) | Y | N/A |
Class l test impulse current limp (10/350µs) | Y | N/A |
Nominal discharge current In (8/20µs) | Y | Y |
Open-circuit voltage Uoc (1,2/50µs) | Y | N/A |
Combination wave (1.2/50µs & 8/20µs) | Y (Class Il, Type 2) | Y (Type 1, 2, 3, 1CA, 2CA, 3CA) |
Voltage protection level Up | Y (Up) | Y (VPR) |
Maximum continuous operating voltage Uc | Y (Uc) | Y (MCOV) |
| IEC61643-11 Determine the voltage protection level (Up) | UL1449 Initial voltage protection rating (VPR) | ||||||||||||
Class I, II, III (Type 1, 2, 3) SPD:
| Type 1, 2, 3, 1CA, 2CA, 3CA SPD:
| ||||||||||||
| IEC61643-11 Operating Duty Test | UL1449 Surge Test |
Apply 15 surge pulses of positive polarity shock current in 8/2µs, divided into 3 groups with each group having 5 surge shocks. Each shock should be synchronized with the power frequency. Starting from a 0° angle, the synchronization angle should increase gradually at intervals of 30°±5°.  | For each applied mode, apply 15 surges of 8/20µs.
 |
| IEC61643-11 Thermal Stabilization | UL1449 Overcurrent abnormal overvoltage |
| The test sample should be connected to the power supply at mains frequency, with the current starting from 2mA and increasing sequentially until the product disconnects from the tester. Throughout the entire test process and after testing, the temperature rise on the surface of the test sample should not exceed 120K. After all nonlinear components are disconnected for 5 minutes during testing, the surface temperature rise should not exceed 80K. | According to the rated voltage of the product and the application system, select the test voltage from the table. Adjust the resistance at this voltage (no SPD in the circuit) to obtain the test current. Then connect SPD in the circuit, power on for 7 hours or until current or temperature reaches equilibrium without exceeding specified values in the table, or until disconnected from AC power. For Type 4CA testing with AC, no forced action is required. For Type 4CA testing with DC, forced action is necessary. The maximum acceptable temperature for metal oxide varistor housing is 85°C.  |
UL classifies SPDs based on their installation location in low-voltage distribution systems. IEC classifies them based on test waveforms.
UL 1449 places more emphasis on the safety of the product itself, with many tests on disconnectors and casings.
1) Current limiting tests, aging tests, using a large number of samples occupying a lot of testing cycles.
2) Surge tests are relatively few, with simpler test requirements and lower surge current values. The standard provides selected surge current values.
IEC 61643 focuses more on the surge protection performance of products.
1) Temperature and humidity aging tests are relatively fewer, with shorter testing cycles, and there are no particularly rigorous verification tests after surge testing.
2) There are relatively more surge tests, with test procedures being more stringent. The standard provides preferred surge current values; most claims come from manufacturers.
Finally, surge protective device (SPD) manufacturers should design products that meet relevant standards according to where the product will ultimately be used and in accordance with the corresponding standards.
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
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