SPD Test Device


For testing the sparkover voltage of surge arresters. The specimen is connected via the included test leads or special test adapters.
  • For routine tests of surge protective devices
  • Compact dimensions
  • Suitable for mains and battery operation
  • Low battery indicator
  • Test leads included in delivery
  • Touch-protected test adapter for modular arresters of the XT/XTU/SP series available as accessory


The PM 20 SPD test device with integrated sparkover detection is used to test Yellow/Line and Red/Line surge arresters with integrated varistor, Zener diode or gas discharge tube. Both the sparkover performance between the connections of the arresters as well as the continuity can be tested. The results can be compared to the limit values specified in the instructions for use. In case of deviations, the arrester or protection module must be replaced. A test adapter with a corresponding support makes it easier to test arresters of the BLITZDUCTOR XT/XTU/SP product family.

Detail 1

Indication of the measured sparkover voltage.

Detail 2

The sparkover performance of gas discharge tubes, varistors and Zener diodes can be tested.

Detail 3

Insulated test leads are included in delivery.

Detail 4

Test adapter for modular arresters.


PM 20

PM 20

Combined device for testing the sparkover voltage of surge arresters (with gas discharge tubes / varistors / Zener diodes). Storage bag and measuring accessories included.


Part No.
Nominal voltage (d.c.) (UN)
Test parameter: Test voltage
Test parameter: Test current (reference voltage)
Measured value indication
Test output sockets
Testing period
Number of individual tests during battery operation
Accessories included in delivery
Dimensions of the storage bag
  • PM 20
  • 910 511
  • 8-12 V d.c.
  • max. 1250 V d.c.
  • 1 mA d.c., constant
  • alphanumeric, eight-digit LCD
  • safety pole terminals (4 mm), positive pole: red colour, negative pole: black colour
  • ≤ 1.5 sec.
  • typically 2000
  • 2 test leads (each 1 m long), 2 safety tapping test clips, 1 plug-in power supply unit (230 V a.c.), 1 storage bag
  • 300 x 110 x 110 mm
  • 1,32 kg
  • 4013364111424
  • 1 pc(s)
  • Specifications (PDF)
  • More
    • Further Pictures
      Further Information
      Product Specifications (Text)


      PM20 arrester test device
      SPD Test Unit for surge arresters based on 
      gas discharge tube/varistor/Zener diode technology
      Allows for mains and battery supply
      Low battery indication
      Storage bag and accessories for measuring included
      Nominal voltage:	8 – 12 V dc
      Test parameters: 
      Test voltage: max. 1200 V dc
      Test current (reference voltage):    1 mA dc, constant
      Dimension of storage bag:       300 x 110 x 110 mm

      delivery and installation.

      Brand: DEHN
      Type: PM 20
      Part No.: 910 511

      or equivalent.
      Installation Instructions


PA BXT Test Adapter

To be connected to PM 10 / PM 20. For inserting and testing protection modules.

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Part No.
For protection modules