Negative cubicles are used to connect the negative return cables, to monitor and to connect negative to ground in case of dangerous over voltage. The design of the negative cubicle is similar to the design of the feeder panel thus granting standardisation of the supply. Inside the cubicle, besides the earthing disconnector, the transducers and the measuring instruments, when requested, can be also present, the negative voltage limiting device; our type LBR, whose application fulfils the EN50122-1 Standards, grants a reliable protection for people and installation safety.
Main features of the LBR are the following:

  • Rated voltage: 750V – 1500V – 3000Vdc.
  • Breaking Current: 900A.
  • Making Capacity: 35kA – 50kA – 100kA.
  • Short Time Withstand current (0,25s): 35kA – 50kA – 100kA.
  • SCR static switch for fast operation (<1ms) when the voltage exceeds the dangerous level of 300V or 600V.
  • Integrated ac-dc over voltage and over current protection relay.
  • Self test function with apparatus in service, with real voltage and current injection.

Our LBR device is also available with the same characteristics in IP30 execution (LBR-n).


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