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How to Check Surge Protection Device

How to Check Surge Protection Device

Created by: Glen Zhu | Updated Date: November 20th, 2024

How to Check Surge Protection Device

Table of Contents

How to Check Surge Protector

Check the Current Situation of Surge Protective Device

  • Installation location and quantity, working status of various levels of surge protective device
  • Wiring method of surge protective device (4P, 3+NPE)
  • The appearance surface of the SPD should be flat, clean, free from scratches, cracks and burn marks, and the identification of the surge protective device should be complete and clear.
  • Status indication of surge protective device.
Status indication of SPD
  • Setting and status of overcurrent protector for surge protective device.
  • Record the model number and main performance parameters of the surge prtective device including: Uc, In, Imax, Iimp , Up etc.

Installation Process of Surge Protective Device

1. The material and specifications of the conductor connected to the low-voltage distribution surge protection device shall comply with the provisions in the table below.

SPD installation locationSPD typeConnecting conductor materialCross-sectional area of the conductor in mm2
SPD connects the phase lineSPD grounding terminal
Boundary between LPZ0 and LPZ1Type 1Copper≥6≥16
Type 2≥4≥6
OtherType 2≥2.5≥4
Type 3≥1≥1.5

2. The surge protection device connecting line should be short and straight, with a total connection length not exceeding 0.5m. If the connection length cannot meet the requirements, a V-type wiring can be used.

The V-type wiring method of SPD

3. The firmness of the connection of the connecting wire.

Check the Energy Coordination of Multiple Surge Protective Devices

1. Requirements: When the first-level surge protection device cannot meet the following conditions between the protected equipment, a second-level SPD should be installed:

  • The length of the connecting lead of the surge protection device does not exceed 50cm, the distance between the surge protection device and equipment is less than 10m, and Up is less than 0.8 x Uw.
  • The length of the connecting lead of the surge protection device does not exceed 50cm, but when the distance between the surge protection device and equipment is greater than 10m, 2 x Up is still less than 0.8 x Uw.
  • The length of connecting lead to an surge protection device exceeds 50cm, with a distance between an surge protection device and equipment less than 10m, and Up/f is less than Uw.
  • The length of connecting lead to an surge protection device exceeds 50cm, with a distance between an surge protection device and equipment exceeding 10m, but when it’s still true that 2 x Up/f is less than Uw.
2. Joint use of four parameters
  • Connection length;
  • Uw: Rated impulse withstand voltage for devices;
  • Up: Voltage protection level for surge protection devices;
  • Up/f: Effective voltage protection level for surge protection devices;

Check the Backup Protection Device (Overcurrent Protection Device)

Requirement: The surge withstand capability of the backup protection device should match the main parameters of the SPD.

  • If the external disconnecting device is an SSD, its product logo, label or test report Iimp, In or Uoc parameters should be consistent with the protected SPD category and match the corresponding parameters of the surge protection device.
  • If the external disconnecting device is a fuse or circuit breaker, its operating characteristics should be coordinated with the higher-level protective device and consistent with the category and specifications specified by the surge protection device manufacturer.
  • If an external disconnecting device is a gG type fuse and it is not possible to obtain a matching gG type fuse specification as specified by the SPD manufacturer, confirm corresponding surge withstand values matching with surge protection device based on rated current indicated in fuse logo, label or product information according to Table 1.

Table 1 – Surge withstand capability of gG type fuses matched with SPD

Rated current of the fuse

Surge withstand capability matched with SPD

The maximum In (8/20µs) kA

The maximum Iimp (10/350µs) kA

8

1.2

0.3

10

1.5

0.3

12

2.1

0.5

16

3.1

0.7

20

4.6

1.0

25

6.4

1.4

32

9.9

2.2

40

12.5

2.8

50

15

3.4

63

19

4.2

80

25

5.6

100

33

7.3

125

42

9.6

160

57

13

200

72

16

224

83

19

250

96

22

315

123

28

400

157

35

500

200

45

630

267

60

On-site Parameter Testing of Power Supply SPD

How to Check if Surge Protector is Working

1. Test parameters
  • Voltage protection level UimA (only for voltage limiting type)
  • Leakage current Iie (only for voltage limiting type)
  • Insulation resistance (including voltage limiting and switch types)
2. Testing methods for voltage protection level Vv, leakage current Iie
  • Applicable only to SPDs with metal oxide varistor (MOV) as the voltage limiting element and no other components connected in series or parallel.
  • Disconnect the backup protective device and use a test pen or multimeter on AC voltage range (250V, 500V) to confirm that the SPD is disconnected from the power supply.
  • Use a lightning arrester tester to directly measure the two wire terminals connected to each phase (L1, L2, L3) of the SPD, or remove the plug-in SPD module for measurement.
  • Connect the lightning arrester tester test wires as shown in Figure 1 to the tested SPD.
Schematic Diagram of Test Connections for Power Supply SPD

Figure 1 – Schematic Diagram of Test Connections

Instructions:

  • For SPDs connected in 2P, 4P configuration, as shown in diagram (a), test wires should be connected to L1, L2, L3 to PE.
  • For SPDs connected in 1P+N, 3P+N configuration, as shown in diagram (b), test wires should be connected to L1, L2, L3 to N (do not connect to PE!).
  • Note: In the parameter testing of SPDs, there is no need to test between N and PE of the SPD.

Tips:

  • Before testing the SPDs disconnect the power supply of the SPD branch and perform voltage verification.
  • After completing the tests reconnect the power supply and perform voltage verification.
3. Correspondence table of the surge protection device (SPD) varistor Vv with its maximum continuous operating voltage Uc, which only has metal oxide varistor (MOV) as the limiting voltage element.
Maximum continuous operating voltage Uc (V) Pressure sensitive voltage Vv limit (V)
AC（r.m.s） DC
50 65 74
60 85 90
75 100 108
95 125 135
115 150 162
130 170 180
140 180 198
150 200 216
175 225 247
180 230 255
195 250 270
210 270 297
230 300 324
250 320 351
275 350 387
300 385 421
320 410 459
340 420 480
350 450 504
360 475 522
385 505 558
420 560 612
440 585 643
460 615 675
480 640 702
510 670 738
550 745 819
580 785 864
600 790 868
625 825 900
680 895 990
750 970 1080
1000 1280 1440
1100 1465 1620
1250 1500 1800

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