What Is the Difference Between Electrical and Mechanical Relay Life?

Updated Dec 21, 2017

Reported In


  • PXI-2520
  • PXI-2521
  • PXI-2522
  • PXI-2523
  • PXI-2564
  • PXI-2565
  • PXI-2566
  • PXI-2568
  • PXI-2569
  • PXI-2570
  • PXI-2571
  • PXI-2586
  • PXIe-2569


PXI Relay Module

Issue Details

In the specifications for our electromechanical relay switch modules, the Expected Relay Life is described in terms of Mechanical and Electrical. What is the difference between these two different specifications?


The expected relay life is divided into two main categories: 
  1. Mechanical Relay Life - this is the number of operations which a relay can be expected to perform while maintaining mechanical integrity. Mechanical life is normally tested with no load or voltage applied to the power contacts.  
  2. Electrical Relay Life - the minimum number of cycles the relay will make, carry, and break the specified load without contact sticking or welding, and without exceeding the electrical specifications of the device. 

Additional Information

  • Relay life is specified as a minimum number of cycles (action of opening and closing the relay) before the contact resistance rises above 1 Ω.
  • Some switch modules are capable of tracking relay usage (How Do I Track Relay Usage on NI Switch Products?).  Refer to the the NI Switches Help (Fundamentals»General Switching Considerations»Relay Operation»Relay Count) for more information.


Not Helpful